Tools and Equipment

Tools

There is no limit to the amount of tools and equipment one can add to their shop but for motorcycle fabrication very little is actually required if you can improvise and aren’t afraid of some manual labor. In fact many of the very best tools are homemade, as you’ll see if you visit our discussion forum and see the pictures of tools, fixtures, holders and improvised equipment people have submitted.

One reason we started the web site, and prepared this manual was we’d been told for far to long that a person couldn’t build a chopper unless they had a fully equipment machine and fabrication shop in their garage. This simply isn’t true. Sure expensive machine tools make the work faster and easier but not necessarily better. If you look around at the pictures I’ve posted at the boards and printed herein of my own garage/shop you’ll see that about the only ‘fancy’ tools I own are a drill press and a belt sander. At one time we had a fully equipped machine shop but to be honest the work I do in the garage with less equipment is of better quality; of course it takes a lot longer to do it.

At a minimum you need a hack saw to cut tubes but a jig saw, reciprocal saw or tubing cutter save a lot of work and make better cuts. If you have a large budget an abrasive chop saw is a good investment.

To measure things and keep everything plumb and square we’ll need steel tape, plumb bob, Machinists Square and level. The small machinists square I use is made by Mitutoyo and is graduated in 32nds and 64ths on one side of the scale and 10ths and 100ths on the opposite side.

To keep track of all the angles a couple of ‘angle-finders’ and adjustable protractors are a real necessity.

Figure 3.1

Angle-finders and protractors are available in a wide variety of styles, types and price ranges. You can get by fairly well with just some cheap simple examples available at almost all good hardware shops or builder supply outlets. Or if you’ve got a big budget you can opt for the far more precise digital models from Tools-Plus such as those made by Bosch shown below.

 

Figure 3.2

There are specialized angle measuring tools used by fabricators and pipe fitters in conjunction in tubing benders. The unit illustrated in figure 3.3 below is just one example.

Figure 3.3

Many fabricators improvise their own personal versions of such tube-levels or angle-finders by creating fixtures that simply hold a conventional level or bubble type protractor.

When I took the picture below I could only lay my hands on two adjustable protractors but I also use the bubble type angle-finders. To mark tubing I use a felt tipped indelible markers and soapstone sticks but to scribe plate stock I use the small metal scribe shown in the snapshot. For measuring small lengths and offsets I use the nine-inch calipers and for longer distance I use a regular old aluminum yardstick, which I find is more accurate than the steel tape for measuring tubing runs. I like these aluminum rulers and have several on hand that range in size from a foot to five feet in length. I’ve also found some use for the aluminum ‘sheetrock’ squares when building jigs. A variety of ‘carpenters’ squares in different sizes are also handy to have around.

Figure 3.4

Other useful hand tools might consist of a few hammers in various weights, rubber mallet, non-mar plastic mallet, medium sized pipe wrench and a wide variety of C-clamps and bar-clamps.

Invest in high quality set of drill bits and a good center punch for precision work but use some cheap bits for day-to-day drilling operations. You’ll also eventually need some taps and dies but it’s better to buy them as you need them as you won’t end up using all the various sizes that come in the typical ‘boxed’ sets. For most Chopper work you’ll only need the following to get started:

 

1/4”-20

5/16”-18

3/8”-16

1/2”-13

5/8”-11

Tubing Notchers

A tubing notcher is basically just a specialized tool designed to cut the fish-mouth recess into a section of tubing that will be welded to another piece of tube to form a connection or junction. An example of a typical fish-mouth, also called a miter or a cope, is shown below.

 

Figure 3.5

When this notched or mitered tube is placed into position against another run of tubing to form a connection the joint looks much like that shown below

Figure 3.6

What makes cutting these notches a real pain in the butt is that the angle between the two tubes is almost never ninety degrees and sometime the two pieces of tubing are different diameters.

It’s almost impossible to effectively build any type of tube frame structure without some fast and easy way to notch tubing. In the old days notches were just cut by eye using a die grinder. I still use this method when I’m in a hurry but it does take time to learn and most people are in a hurry to get started. For more critical work most fabricators just chucked- up a metal cutting hole saw in a drill press and tilted the table as needed for any particular angle but it was a pretty slow operation.

Fortunately at some point in time during the late sixties some guy developed a little device called the ‘Joint-Jigger’ that used regular metal cutting hole saw bits mounted to a drill driven sliding shaft that ran through a bushed block that could be adjusted for various angles. It was crude but very effective and much faster to set up than the old drill press process. Ninety percent of all tube notchers made today are still based upon this original design seen below from Van Sant/

Figure 3.7

There are at least five variations of this basic notcher being sold under a variety of brand names. Each has it’s own unique characteristics and prices range from around $69 at Harbor-Freight to well over $250 through some speed shops. Of course the higher priced units have more features and are generally more accurate.

Figure 3.8

The JD Squared notcher is shown above and the JMR unit is illustrated below.

 

Figure 3.9

If you buy one of these ‘jigger’ type of notchers try to find one that swings thru sixty degrees of arc. Cheap models only have a forty-five degree range of motion that isn’t enough for most cycle frame miters.

The ‘Jigger’ type of notcher is rather limited in application and has a few drawbacks that you might consider before buying one. First of all as mentioned earlier they have a restricted range of motion. Secondly, they can’t do a compound miter where one tube intersects another at an angle outside of the X-Y plane. These notchers are relatively slow, use up a lot of hole-saws and aren’t extremely accurate. Even the expensive ones sometimes need some tuning-up by shimming or surfacing down the shaft carriage to get the saw to cut exactly in the middle of the tube.

Another variation in the less expensive type of notcher is the so-called ‘guillotine’ type that uses a lever driven blade to chop segments out of the tube as seen below from Williams Low-Buck tools. These are extremely fast but it does take some practice to get good with them.

Figure 3.10

Several manufacturers sell similar hydraulically operated units but they are relatively expensive and not nearly as fast to operate. The one shown on the next page is from Mittler Brothers.

 

Figure 3.11

If you do more than a few frames every month you can step up the ladder and buy a variety of electrical or hydraulic operated notchers but the base price for such equipment usually starts at around $800 and goes up to several thousands.

 

Figure 3.12

Figure 3.12 is an electrical End Mill type notcher, again sold through Mittler Brothers and very popular in mid-sized chassis operations.

Figure 3.13 is another higher end electrically driven notcher but this type uses abrasive belts to cut the fish-mouth.

 

Figure 3.13

If you’re only going to be building one frame and you have a disc or die grinder that’s really about all that you need. Used in conjunction with the tube-miter program available on the web site that creates templates for virtually any size of tube or any intersection angles you can cut a good accurate fish-mouth in any type of tubing in just a few minutes.

If you’re doing a couple of frames every year then one of the simple ‘joint-Jigger’ type notchers is more than up to the task. It’s only when you start to do a couple of frames every month that you really need to look into the larger machines. Even then many mid-sized operations will continue to use simple hole-saw notchers but they modify them for specific applications.

If you buy this type of notcher try to find one that swings thru sixty degrees of arc. Cheap models only have a forty-five degree range of motion that isn’t enough for most cycle frame miters.

This particular type of notcher is rather limited in application and has a few drawbacks that you might consider before buying one. First of all as mentioned earlier they have a restricted range of motion. Secondly, they can’t do a compound miter where one tube intersects another at an angle outside of the X-Y plane. These notchers are relatively slow, use up a lot of hole-saws and aren’t extremely accurate. Even the expensive ones sometimes need some tuning-up by shimming or surfacing down the shaft carriage to get the saw to cut exactly in the middle of the tube.

I’ve also seen some excellent notchers that have been custom made in some shops so you might want to do some experimenting in this area as well.

Regardless of the type of notcher you end up with it is important to understand that the miter should not have sharp edges or the welder will just burn them off. For example if you use a 1.25” hole saw to miter 1.25” tubing the resulting cut end will have almost razor sharp edges and look like a round knife blade as seen in figure 3.14.

 

Figure 3.14

The scribe points to the ‘knife-edge’ on the lower portion of this fish-mouth. The upper edge has already been ground down to provide the full tube wall thickness along the line of the prospective weld. You can see that it appears blunt.

As mentioned earlier you can always build your own notcher or modify existing models. I personally buy the cheapest hole-saw notchers when they go on sale and then use the bits and pieces to make application specific units or modify the stock notcher in some manner to work better for certain tasks. Figure 3.15 illustrates only a few of the various modified notchers and accessories I use on a routine basis.

Figure 3.15

I personally hate ‘adjustable’ equipment of any type so I’ll usually make all of my notchers fixed by just drilling and taping for a setscrew in the adjuster plate. Often I’ll mount the factory supplied tube clamp on the back plate in a reversed direction to increase the angle of cut.

Another handy tool to have around the shop is a little gadget called the Longacre Pipe Master that is actually a set of specially designed collars that slip down over a tube connection and forms a boundary line you can trace around for the correct miter at virtually any possible intersection angle. You need one PipeMaster for each tubing size you typically work with but they only cost about forty dollars each and are well worth it.

 

Sandblasters

For cycle work you can get by with a very small blaster. I use a very cheap little ‘bucket’ model I picked up about fifteen years ago. It holds two gallons of sand, which is more than enough for an entire frame on a single fill up. It is the so-called ‘open’ type, which is usually considered a disadvantage, but in the case of bike building it’s a blessing in disguise since you can change media very easily. The little blaster I own is far to small for doing big jobs like a car fender which would take you about four hours and five ‘buckets’ of sand but it’s more than adequate to blast an entire cycle frame in about thirty minutes on one load of media.

Blasters are very messy and I don’t use this particular model with a cabinet so what I do when I need to blast something is to haul it outside on the ‘downwind’ side of the house and do my work letting the debris drift over into my neighbors yard when he’s at work. That way my side-yard stays clean and my neighbor still can’t figure out why his patio is always covered with very fine sand. A visitor to the site suggested that I could use a cheap ‘pop-tent’ as a walk-in blasting cabinet so I could recover the used sand. That was one of the best tips I’ve received in years.

By the way you have to use ‘dry’ sand in a blaster and not all lumberyards sell the good stuff (dry quartz plaster sand) so you may have to buy blasting media over the net and have it shipped to your location.

 

Portable Power Tools

The most important power tool in my estimation is a small 3.5 to 4 inch mini grinder/sander and unless you like changing wheels buy several cheap models so you can keep one set up for grinding, one for disc sanding, one for wire brushing and one mounted with a very narrow abrasive cutting blade. I’ve personally used every brand of small grinder on the market and the only one that I’ve ever actually worn out was one of the most expensive models so I stick with the ‘cheaper’ brands nowadays.

For a drill motor you should have a nice big half-inch industrial strength 115/120V power drill and a couple of small three eights inch battery powered units for the lighter work. Buy extra batteries and always keep one charging.

If you can afford it an electric die grinder is a very handy tool for dressing up tube cuts and for smaller detail work a Dremel rotary grinder is indispensable. I also use one of the so-called ‘flexible’ shafts that mount various grinding stones in a drill chuck and drive it from the arbor on my bench grinder.

A reciprocal saw (Sawsall) gets a lot of work in my shop and even though they are relatively expensive they last an awfully long time

If you plan on doing any sheet metal work you’ll also want a variable speed disc sander/polisher, small palm sander and a wide variety of sanding blocks.

 

Stationary Power Tools

In order of importance I would have to rank a bench mounted combination disc/belt sander as number one, a bench grinder as number two, a drill press as number three and a heavy-duty band saw as number four.

When you start getting serious you can add a milling machine and a metal lath to the shop or save some cash and farm the machine work out to a local shop.

And again if the budget can stand it a good 5hp air compressor with pneumatic sander, die grinder and sheet metal nibbler is almost a necessity in a larger shop.

 

Chop Saws

For wood workers the machine is called a Chop Saw, for metal workers the device is typically called an Abrasive Cut-off Saw but its still a Chop Saw as far as I’m concerned.

These machines are nice to have for cutting materials to length but in my personal opinion they shouldn’t be used for cutting chopper frame tubing. Abrasive blades cut by heat action and nobody can argue this point. The abrasive grit in the blade is harder than the material being cut and one or the other has to give. Under most circumstance the material being cut melts before the grit particles. My reasoning behind this statement is that the heat generated by the abrasive blade when it’s used on thick walled tubing can do one of two different things. If the heat is excessive, which it usually is, and the cut piece cools rapidly it becomes hardened and brittle. If the cut piece cools slowly it can become annealed and soften. Regardless of what happens however the ends of thick-wall tubing cut with an abrasive saw are definitely altered from the natural state of the native steel compound contained within any particular tubing. This fact is easily seen by observing the ‘color bands’ that extend back up into the tube from the face of a typical abrasive cut. If you look closely at the ends cut on an abrasive cutoff saw you can see all the colors of the spectrum ranging from dark blue (570 degrees) near the edge of the cut and progressing up through full blue, dark purple, full purple, brown purple, spotted red, brown-yellow, dark yellow, straw yellow, light yellow, and pale yellow before you get back to the natural color of the tube in question. It like creating a ‘heat affected zone’ (HAZ) before you even do any actual welding.

If you weld two pieces together that have been cut with an abrasive saw you will see a considerable difference in the characteristics of the weld as you move through the various ‘color bands’. This doesn’t bother a lot of people but it does bother me but I may be paranoid.

Using abrasive cutoff saws on thin wall material isn’t a problem since the blade going through minimal material thickness doesn’t have a chance to generate any significant heat and I routinely use such saws to cut 0.083 and thinner material in our shop on a daily basis. I use a hacksaw, reciprocal saw, band saw or regular old tubing cutter if I’m cutting any 0.095 wall or over tubes.

There is an alternative to abrasive disks. Almost all manufacturers of saw blades make products designed specifically to cut metal. Usually they will provide two general products. One designed for ferrous and the other for non-ferrous metals. For mild steel you’ll need blades for ferrous material. These blades come in a variety of diameters with different arbor sizes to fit most common circular saws and cut-off saws. Outwardly these metal cutting blades look almost exactly like the saw blades we’d use to saw up some bookshelves for the old lady.

The biggest advantage of using a metal cutting saw’ blade’ as opposed to an abrasive ‘disc’ is that the blade produces very little residue or ‘abrasive dust’; in other words it produces a very clean cut with minimal heat transfer back into the material being cut. They also cut much faster and make a far cleaner and more accurate cut than abrasive blades. These blades are four times more expensive than abrasive disks but once you’ve used one you’ll never go back to abrasives again.

 

Safety

While we’re on the subject of blades I think it’s important to point out that circular saws, chop saws, cut-off saws and even disc grinders can very quickly cut off your fingers if you’re not careful. If mishandled, at the very least, these tools are all capable of rendering your hands useless even if you manage to save your digits.

Besides cutting off your appendages many power tools, especially those that eject residue from their action such as grinders and circular saws can very easily send material into your face and eyes. Grinders are probably the worse offenders but circulars saws are almost as bad. It is imperative that you wear safety glasses in the shop and its not a bad idea to wear a full face shield if your working with high RPM types of tools such as die grinders, end mills, disc grinders and portable circular saws. To be very frank I think people who don’t use safety gear are idiots. There is nothing macho about being able to withstand the impact of wire strands thrown out from a wire-brush disc wheel.

 

Clamps

In the milestones of human evolution fire is ranked as one of the greatest all time inventions followed by the wheel and the lever but the guy who invented C-clamps has to rank up there pretty high as well.

In my personal opinion there is no way that you can own to many ‘C-clamps’ in even the smallest shop. Good clamps are not cheap but cheap clamps have a tendency to break right when you need them the most. Welding has become such a popular home-based hobby that you can now buy clamps, at almost any hardware store, that have copper coated screw threads so weld splatter doesn’t mess up the threads.

There are also a huge variety of specialized clamps available for chassis work like the two shown below sold by Van Sants.

Figure 3.16

When I go into a hardware store or stop by a garage sale I automatically focus in on clamps of any type always looking for something that I can adapt or modify for frame building.

Many of you reading this will probably already have a huge tool and equipment selection that you’ve used either in your work or as part of past endeavors with cars, trucks or street bikes. There will be others however that are starting from scratch and if that’s the case I strongly recommend that you start visiting some garage sales. It’s amazing what you can find for next to nothing if you hit the streets first thing every Friday and Saturday morning.

I’ve known people who have picked up lathes and milling machines for a few hundred dollars at garage or estate sales and only last week I bought a brand new, never been used Milwaukee portable metal-cutting band saw for fifty dollars.

Along the same line of thought always keep in mind that you can usually make a tool or at least improvise a specialized tool from an existing tool or tool parts without spending very much money. This can sometimes come back to bite you in the ass however as some tools simply can’t be successfully jury-rigged. A good example is trying to convert a wood band saw into a metal cutting band saw. It’s usually just not cost effective and the resulting conversions generally don’t work to well.

Eventually you’ll have to fact the facts of life and realize that unless you have a bunch of money laying around you’ll probably have to call upon friends who do have some of the more expensive equipment, or even pay a shop, to have some work farmed out instead of buying an expensive tool for a one or two time usage.

If you wait until you have each and every specialized frame-building tool known to exist you’ll probably never get your Chopper project started and in fact until you’ve started a project you won’t really know exactly what type of gear you’ll need to begin with.

 

The Tube Bender

You don’t need to buy a tube bender in order to get your frame built. There are literally thousands of small shops and independent builders around the world today who would be more than happy to bend tubes for your project. Sometimes you may have to pay a nominal fee per bend while other times you might get the work for free or maybe a six-pack.

If you decide that you can indeed afford a bender however be assured that you can make it pay for itself in a very short period of time by bending parts for other biker’s, hot-rodders and off-roaders. A good tube bender is one of the best investments in equipment a small fabrication shop can make and even used benders command premium prices on the open market so your investment will never go wasted.

Even if you’re on a very tight budget don’t waste what little funds you might have on one of the cheap pipe benders being sold at discount stores and on eBay as being ‘chassis benders’. These benders, a typical example is shown below, aren’t even very good for bending pipe to begin with let alone frame tubes.

Figure 3.17

There is huge difference in the dies and even the basic design of pipe and conduit benders as opposed to real tubing benders and for frame work there just isn’t any real shortcut you can take beyond spending a lot of time and money trying to adapt a pipe bender for tube work.

In today’s market place one can buy a tubing bender for just about any application imaginable with prices ranging from a couple hundred dollars to several tens of thousands of dollars. The price of the bender is directly related to what type of tube it’s intended to bend. If you’re bending extremely thinned-walled tubes into tight radiuses, or conversely, very thick-walled tubes into tight radiuses, you’re going to shell out some big bucks for some very specialized equipment called ‘Mandrel’ benders.

Figure 3.18

The mandrel bender above, from Transfluid, will bend 3” diameter tube around a 1.5” radius but it costs thirty-five thousand dollars. There are perhaps as many as a dozen different makers of mandrel benders and each maker has several different benders in their product line with prices ranging from around $3500 and going up to the stratosphere depending upon your particular application. A medium sized chassis shop might need a mid-line unit, usually in the ten thousand dollar range to do NASCAR or Pro-Fuel frames.

Fortunately for most of us performance freaks the average Hot Rod, Dragster, Sprint car, 4x4 or Chopper uses tubing that is relatively thick-walled and easy to bend with fairly primitive technology which means that we can afford to do the bending ourselves with simple machines that are financially within almost everyone’s means. The average performance enthusiast doesn’t need a ten thousand dollar mid-range bender designed to bend .035” wall chromoly along a 3.5-inch radius. The big-name racers might need something along these lines but then again the big-name racers aren’t on a limited budget like the rest of us.

There was a time back in the old days when the only ‘real’, economically viable, tubing bender available to small-time performance fabricators was the ‘Hossfeld’. This particular bender is still being manufactured and is very popular for shops that do a wide variety of general fabrication work since it will bend virtually any shape of steel you’re likely to encounter such as round tubing, plumbing pipe, steel angles, channels, rectangular and square tubes and even solid bar stock, plus flat strap. It’s just a pure workhorse and has the benefit of about sixty years of debugging behind its basic design.

I don’t think I’ve ever been in a general fab shop that didn’t have at least one Hossfeld bender among their equipment inventory. I recently attended an equipment auction at the large fab shop where the owner was retiring and moving to Oregon. The only piece of equipment in the entire plant that wasn’t for sale was the little Hossfeld bender, which he was going to take with him. This simple fact says a lot about the importance and intrinsic value of a good bender as compared to other shop equipment.

Figure 3.19

When I first started to build quarter midget and midget frames in the sixties I used an old recycled Hossfeld bender like the old pictured above. I owned it for twenty years and eventually sold it for four times what I originally paid to another builder who was just starting out. Over the years that particular unit has changed hands about ten times but it’s still being used today in a Stockton boat yard.

For pure versatility these units can’t be beat even today but for most bike builders it’s actually a little over-kill since what we’re typically looking for is just something to bend some round tubing without kinking.

In the late sixties and early seventies we started to see a new type of bender on the scene that was specifically designed just to bend racecar chassis and cage tubing. Like the Hossfeld it relied on die and lever operation but was significantly different in basic design and much more specialized for the performance fabricators as opposed to the general fabrication shop. I honestly don’t know who ‘invented’ these particular benders but eventually the company that first came to mass-produce them was called JD2 and even today most people refer to these benders as JD’s or ‘ratchet’ benders even thought they only look like they have a ratchet mechanism.

Figure 3.20

I bought my first unit around 1980, called the Model Two, it was a wonder compared to the old Hossfeld as far as throughput was concerned. For a frame builder these machines were heaven-sent. They were relative cheap; you could bend tubes to almost any angle imaginable and they were extremely quick and easy to operate. It was obvious from the get go that these machines were specifically designed for chassis fabrication and little else. For versatility they sucked but for frame tubes they were a wonder. I bought the model three a few years later and still use it today. For the type of chassis work I do I’ve never found this bender to be lacking in any respect which is why I’ve never bothered to upgrade to the newer models. I’ve had friends bring over tube that they’re so-called high-power hydraulic benders couldn’t bend and with a little cheater bar this little JD can handle just about anything up to 1.5 inch by .25 wall with a five foot extension handle.

There are at least five different companies now making very similar benders, each with some specialized design feature which gives them some unique difference to avoid patent issues but they have all evolved from the original pattern

Figure 3.21

Figure 3.21 is JMR manual model and figure 3.22 is a Pro-Tools model 105. You can see that they’re very similar to the original JD model 3.

Figure 3.22

The Hossfeld, JD2, JMR’s and some of the Pro-Tools benders are typically called ‘horizontal’ benders since the tubing is bent on its ‘side’ so to speak and the bends are made in a horizontal plane that is parallel relative to the shop floor.

In recent years there has been increased interest in ‘vertical’ benders where the bends in the tubing lay in a plane that is perpendicular to the floor. Vertical benders have actually been around longer than horizontal benders and in fact most of the old original pipe and conduit benders were vertical models.

Vertical benders at first glance seem to be cheap and easy to build so they do have a following from the do-it-yourself crowd as seen in the pictures that follow.

Figure 3.23

The bender above was fabricated by a boat-builder and if you carefully compare it to other home-built vertical benders you can readily see that he’s made some improvements in the basic design popularized by Blind Chicken racing as seen below.

Figure 3.24

If you spend a considerable amount of time on the Internet you’ll eventually find all kinds of links to homemade tube benders and bender ‘plans’ and with the exception of our plans, almost all of them are of the ‘vertical’ design using bottle jacks as the driver.

There is a popular misconception that vertical benders are simpler and cheaper for the average enthusiast to build at home but this simply isn’t the case and in fact you can build a good horizontal bender in less time for much less money.

 

Figure 3.25

This unit, as seen in Figure 3.25, posted on the discussion board by Hose-Dragger, was built for under a hundred dollars, including the die. It’s a simplified derivative of the JD2 type.

Ready-made vertical benders as opposed to home-built units are certainly more expensive to purchase than horizontal benders. The Pro-Tools model 200 vertical without any dies is almost $500 while the JD2 model 3 horizontal is just $295.

 

Vertical or Horizontal – The Real Advantages and Disadvantages

There is always an ongoing discussion among builders as to which type of the bender is the best for general frame fabrication. Proponents of the vertical models insist that it’s easier to bend frame tubes vertically because the tubing, when setup in the bender, ‘points’ in the same direction as it would in a finished frame so it’s easier to visualize at what rotation you need to make each particular bend in a typical frame. Up to a point I have to agree with this statement but as you gain experience with bending it becomes much less of a factor.

Supporters of horizontal benders are quick to point out that vertical benders can’t do any bends that are much over 90 degrees because the bender frame prevents the tubing from doubling back on itself. This is indeed true and in some instances it makes a vertical bender impractical for general car and bike fabrication duties. Most horizontal benders will easily do complete 180-degree bends; even 220 degree bends or complete circles depending upon the particular model. Take at look at the tube being bent in the Hossfeld in figure 3 again to get an idea of what I’m talking about.

Vertical advocates say that they can bend larger and thicker walled tubes in their machines with 15-ton bottle jacks than can be bent with manual horizontal benders. This claim is pure bull and total fiction since the capacity of any bender is based upon the strength of the frame and more importantly the pins used in its construction.

Both types of benders can bend the same specification of tubing and neither has an advantage here. In fact the tall vertical benders may actually be at a structural disadvantage, which is why all commercial benders designed specifically to bend extremely large or thick walled tube are of the horizontal type.

Vertical benders in general do take up less floor space than horizontal benders but on the other hand there are some structural runs of tubing that just can’t be made on many verticals since the tubing is so low to the shop floor. As a result some builders of verticals move the follow bar up much higher as seen in the picture of Glenn’s bender as opposed to the more conventional model illustrated in figure 8.

There is no ‘rule’ that says a horizontal bender can’t be mounted on its side however if the owner likes the tube orientation of a vertical bender. David posted these snapshots showing how he made two sockets in his JD stand so he can mount his bender either horizontally or vertically depending on the type of bends he’s making.

 

Figure 3.26

Figure 3.27

This arrangement gives you the best of both worlds and in addition it is very easy to add a hydraulic ram to any horizontal bender if you really think you need it. This flexibility of so-called horizontal benders pretty much invalidates most of the arguments in favor of vertical types to begin with but sometimes you just can’t change people’s way of thinking.

In some instances vertical benders have a disadvantage over horizontal benders with respect to doing accurate repeatable bends on long runs of tubing since the follow bar may waver slightly from side to side, especially if bending DOM tubing that has an inherent twist to it.

I can’t say for sure but I suspect that this is probably the primary reason most large frame builders don’t use the vertical benders for production work.

Vertical benders, on average weigh about three times more than horizontal benders. In fact you can pack a horizontal bender in a small suitcase and carry it on an airplane if need be. I don’t recommend it but I’ve done it when I’ve had to set up a booth at shows.

My personal opinion is that properly designed and well-built vertical benders are as good as most properly designed and well built horizontal benders. I do think however that you can build yourself a good horizontal manual bender for a whole lot less money than a good vertical bender and that the horizontal bender is far more versatile in the long run.

It may be interesting to note that some of our site members report that none of the chopper companies they visited who currently sell or post plans for vertical benders actually use them for their own fabrication operations. I think that this single fact says a lot about vertical benders. They make a lot of money for people who sell them, either as plans or kits but those same chopper makers may not use them for their own projects.

 

Manual or Hydraulic

For 99.9% of all fabrication work done on the average Hotrod, Gas-Class Dragster or Chopper there is no reason whatsoever to use hydraulic assist on a bender and in fact for production work in a small shop hydraulic benders are actually to slow to keep up with the pace of production and become a hindrance rather than a help. Hydraulic rams certainly impress the customers but they typically don’t do much to help the shop staff unless they’re a lazy bunch to begin with. You can buy two manual benders for the price of just one hydraulic unit. Which choice do you think will be more productive as well as more cost effective?

On the few occasions when I’ve personally needed to bend 2” diameter, .25”wall material it has made more sense to farm it out to a large fab plant in Sacramento who did the work for $25 per bend. The vast majority of framework involves tubing that ranges from 1 to 2-inches in diameter with wall thickness from .063 to .134 inches and this type of material is very easy to bend with manual operation.

Many people are under the mistaken impression that a hydraulic bender is ‘stronger’ than a manual bender or that hydraulic units make better bends or that hydraulic units can bend thicker tubing than manual benders. Statements like this just aren’t true when they’re applied to the average mid-range small-shop benders that most of us are likely to contemplate buying.

The whole issue of manual verses hydraulic was refreshed for me personally when I watched the new Ron Covell frame building video where he uses a very nice little hydraulic bender. As I watched the bending scenes I was in agony wondering how long it was going to take to make each and every single bend, especially as he tried to feather the pump towards the end of the bends so they’d be accurate. There is no doubt that you don’t have to exert any effort to make a bend with a hydraulic unit but at least a manual bender allows you to make a bend in few seconds as compared to minutes.

Ironically the bender used in that video at $1300 is only rated to do a maximum of 1.5”x.120 wall tubing while the manual version is rated at 2.0”x.134” wall at half the price.

The biggest advantage a manual bender has over a hydraulic unit, if push comes to shove in the shop someday, is that a manual unit will allow you to break the rules and use a really huge cheater bar to do something that you probably really shouldn’t be doing in the first place. I’ve broken the rules so many times that I can’t count but I’ve never broken the bender yet and I’m sure that it’s been pushed about a hundred times past it’s factory ‘specifications’.

In over forty years of doing general fabrication I only know of one instance where a builder actually bent the frame on a JD2 model 3 trying to bend 2” diameter .25 wall tube into a 90 degree angle. The bend by the way was successful but he had to buy new arms for the bender. The only reason he tried it in the first place was because his four thousand dollar hydraulic mandrel bender wouldn’t budge the tube to begin with.

In the end it’s a matter of person preference and economics versus capacity. You can buy a much more powerful manual bender that will handle a wider range of material for less money than any hydraulic unit on the market no matter which company you choose to buy from. Keep in mind that it’s very easy to add hydraulic assist, even temporarily, to almost any cheap horizontal bender.

 

Dies and Follow Bars

The single biggest cost of a bender assembly is the die itself. The bender frame is actually pretty cheap. Very cheap if you build the frame yourself but a typical die and follow bar from most manufacturers starts around one hundred and fifty dollars and goes up depending on the size.

At one time some of the upstart companies tried to hold costs down by selling dies and followers that were made from aluminum but the failure rate was so high that most makers have now switched back to steel. Some places still sell aluminum followers but you want to avoid these if at all possible since they don’t hold up very well over time and tend to widen out with a lot of use especially on thick walled tubing.

Thanks to the recent popularity of chopper building they are now several independent sources of bender dies. A couple of our own discussion board members sell die sets at very reasonable costs and there are other machinists posting at other boards who also offer quality dies for several of the more popular benders.

A complete starter set of dies for the average small fabrication shop would consist of .75, 1, 1.125, 1.25, 1.375 and 1.5 inch sizes based upon a 4.5 centerline radius. As you can imagine this can get to be pretty expensive so most people only buy the size they need when they actually need it. For specifics about die sizes and bending radiuses visit the various manufacturers web sites.

As a very general rule of thumb the minimum centerline radius for a die is three times the diameter of the tube but most builders have more or less standardized on the 4.5-inch radius for about 90% of most frame parts.

For handlebars, braces, brackets and smaller parts using 1 inch or under tubing the 3.5-inch radius dies are very handy.

Unfortunately dies from one maker usually won’t fit a frame made by another. For instance you generally can’t use a Pro-Tools die in a JD frame and vice versa so you have to do your homework when dealing with independents and verify that their product is indeed 100% compatible with your particular bender.

 

Welding and Welders

Before we begin to talk about welding and welders it should be understood that what follows is specifically restricted to the fabrication of Chopper type motorcycle frames. It may not apply to racecar frames, dirt bike frames, Moto-cross bikes, road racing bikes, bicycles or any other type of two, or four-wheeled vehicle. The reason we make this disclaimer is because choppers are usually not subjected to the same types of loads and forces encountered in lighter-weight high performance machines yet chopped bikes must be able to withstand a significant amount of stress, but in general, for shorter durations.

High performance racing motorcycles are generally built from thin wall tubing and have highly triangulated frames for strength while choppers are customarily made with thick-walled tubing and have very little triangulation, relying instead on the bending strength of the tubing to provide frame rigidity. In fact most old Big Twin and custom chopper frames are pretty poor examples of good frame engineering principals. Welding methods and techniques used for the construction of lightweight off-road or road racing frames may be inappropriate for heavier frames designed for use on streets and highways. A properly designed motorcycle frame should be designed so that the tubing lengths in the frame itself take the stresses and loads and not the welds at the various connection points. Frame failures, when they do occur, are usually the results of poor engineering design and not poor welds in themselves.

The second point that needs to be understood is that 90% of the factors that go into a successful weld involve the proper selection of material, cleaning, preparation, fit-up and the skill of the individual welder regardless of the equipment or type of welding being done. This point cannot be overemphasized. The selection of Gas, Wire-Feed, Mig, Tig or Stick is not nearly as important as the skill one possesses with whatever welding rig is at hand and the care taken to clean, dress and properly fit the parts to be joined. A good weld, performed by a skilled welder, with any one of several different methods that are available today will be as strong or even stronger than the material being joined.

The third point, often underestimated by many, is that in order for a person to be a ‘good’ welder they have to weld on a more or less regular basis. Practice will hone your skills to a certain level, and like riding a bicycle you’ll never forget how to weld, but day in day out production welding gives you the consistency to make effective welds each and every time you strike an arc. I’ve been welding for over forty years but its been thirty since I welded every day and the occasional work I’m doing today is at least 75% below the quality I did when I was welding to make a living. A welder’s job is to apply his or her complete and total concentration to each and every weld. You can’t do good welding and be concerned with other matters or distracted by other facets of the bikes construction. It is possible to run the shop and to do chassis design and tube fabrication and fit-up all by yourself but when the time comes to do the welding that is all you should thinking about.

Unfortunately welding is not something that you can completely teach yourself from books or videos. This is one of the few arts or skills that require a teacher’s assistance and constant practice. That teacher can be a friend who welds at his or her job or an instructor at a trade school or community college but to fully develop your potential you will eventually have to seek out the guidance of a qualified welder to critique your work and to provide practical advice on how to improve your performance.

When I first started messing with steel I worked at an auto salvage yard. We also built sprint cars on the side but as the low man on the totem pole I was shown how to run a cutting torch and I cut cars apart eight hours a day for a whole summer before the guys would even let me watch them weld up sprint frames. The next year I was shown how to strike an arc with an old Lincoln Buzz-Box and to lay down some bead and turned loose on welding mounting tabs and brackets which my boss would promptly bust off with a hammer since the welds looked like crap. One night his son took me aside and let me watch him weld reinforcing plates on a frame. Wearing my hood I could get right down and up close to watch him string bead and that’s how I learned the real basics of general purpose arc welding. I started to comprehend what the term ‘penetration’ was all about and I saw first hand how one manipulates the weld pool and keeps the heat evenly distributed between two separate pieces of material. One evening spent with this guy was worth a year of trying to learn welding on my own. The very next day my boss quit bashing my mounts off the frames and by the next summer I was welding up chassis tubes.

Getting off the track for a moment I have to say that welding is one of the few ‘trades’ that’s actually more akin to a ‘profession’. My father was a design engineer and I wanted to eventually follow in his footsteps but he always encouraged me to go to a trade school instead of a college and learn to become a welder. In his opinion welding was one of the ‘old’ alchemists endeavors that combined very significant amounts of raw brainpower with artistic talents and skills that engineers did not have the opportunity to engage in. Unfortunately I didn’t follow his advice until much later in my life but I can say from experience that learning to become a welder is one of the most satisfying things one can do if you want to combine a wide variety of disciplines, skills and talents.

There is a dangerous tendency today, spawned by the fad of custom bike building, to judge the effectiveness of welds by their outward appearance. Many believe that the nice smooth beads left behind by Tig welding produce better joining than the less smooth beads that result from wire feed or stick welders. This isn’t necessarily so and in some cases a nice clean Tig weld that looks very good on the surface doesn’t have the penetration of it’s less attractive stick bead counterpart. It is sometimes useful to remind ourselves however that the objective of welding is to melt the metal in two different pieces of steel and blend the molten material together until the two pieces, in effect, become one monolithic block. To often people think of welding as ‘molten-gluing’ where you glue two pieces together with a melted ribbon of steel represented by the weld bead.

Unfortunately I think that the manufacturers of welding equipment have done much to foster this misconception with their ‘new’ approach to welding which involves low-cost wire-feed welding machines and the technique of ‘dragging’ the electrode across the work while relying on the arc by itself to do all of the work. The highly popularized low cost wire feed welders and the ‘new’ techniques being pushed by several manufacturers do indeed produce a fairly good weld in the hands of people who only need to do some occasional welding on components that you or I wouldn’t consider being critically important. I seriously question however whether such techniques are adequate for welding together the bits and pieces of a cycle frame that might be hitting four-inch deep potholes at eighty miles an hour or better.

Throughout this section and in other sections you will often see references to ‘thin-wall’ and ‘thick-wall’ tubing. As these terms are related to cycle frames it is my opinion that the transition point between thin and thick occurs somewhere around 0.083 inches in wall thickness. Other writers may have different opinions. I personally think that 0.095” and over walls are thick and that anything less than 0.083” is thin but this break-off point is related to Big Twin cycle frames and not road racers where 0.063” wall tubing is common and 0.034” is not unheard of. This distinction may seem irrelevant but as it relates to welding for custom choppers it is vitally important.

In the descriptions that follow it is important to understand that what we’re talking about relates to welding chopper motorcycle frames and that such frames typically use thicker walled tubing than lightweight street bikes and road racing machines.

What follows is an extremely generalized and summarized description of welding processes and techniques intended to provide a broad overview of the field. Readers interested in learning the specifics of any individual area or specialty are encourage to review the information published by the manufacturers of welding equipment such as Lincoln, Hobart and Miller and to visit the web sites published by independent and individual welders listed on the links page.

 

Processes

In the early days almost all cycle frames were fabricated by what is commonly called the ‘sweating’ method where tubes are inserted into sockets that are part of what is called a frame connection casting. These casting are not cast iron but rather cast or forged steel so they can be welded but this joining method is similar to soldering copper pipe fittings except that brass alloy material is used. The socket is heated and the brazing rod is held on the joint until the rod melts and the pool is sucked up inside the joint. The tube is held tightly in the socket by the ‘adhesion’ of the brass filler material unlike the ‘cohesion’ method used in welding where two materials are completely amalgamated and fused together. Sweated lug construction is a lot stronger than one would imagine and the brazing alloy itself has a tensile strength of around 63,000psi. Sweating and brazing frames is still perfectly satisfactory for restoration work and reproduction fabrications but it is imperative that the lugs be properly designed to carry the connection loads.

For ninety percent of Chopper frame fabrication however you’ll be using one or more varieties of arc welding equipment. In its most basic form this process involves the use of a controlled ‘short’ in a wiring circuit. If you’ve ‘sparked’ a wire when trying to install a light fixture you’ve already done some ‘arc’ welding. In its refined form an arc welder uses electrical amperage between a positive and negative pole to create an arc of electricity and the heat generated by this ‘arc’ is hot enough to melt most common metals. This process is basically miniaturized and controlled lightening which is one reason for the alchemical reference mentioned above.

General arc welding involves creating a ‘ground’ which is usually the pieces to be welded and then adding the ‘arc’ in the form of the ‘hot’ wire placed near but not quite touching the ‘ground’. When you move the ‘hot’ wire near the ‘grounded’ piece of metal electrons will jump across the gap, seen as sparks or the small lightening ‘arc’ which creates so much heat that both the grounded and ‘hot’ pieces begin to melt. The hot component of this ‘circuit’ is called the electrode and can take the form of a rod about twelve inches long or a continuous spool of wire about 200 feet long. This electrode is melted or ‘consumed’ a little at a time as long as the arc is being maintained. The melted material from the electrode (or wire) forms the ‘filler’ that is needed to make up for material that is literally vaporized in the high heat of the welding arc.

Regardless of what you may have heard on countless Chopper discussion boards there is absolutely no difference whatsoever in the characteristics or quality of welds done with conventional ‘stick’ type arc welders and the more modern ‘wire-feed’ arc welders. Both machines and techniques use an electrode to generate an arc that melts the base materials and the material from the electrode forms the ‘filler’ for the weld bead.

I’m asked about a hundred times a day why wire-feed welding seems to be the ‘preferred’ technique pushed by the ‘welding industry’ and the reality of the situation is that almost all welding is charged by the ‘inch’ and that the typical welder can lay down two to three times as much bead with a continuous wire feed machine as opposed to changing electrodes and ‘dressing’ the weld every minute or so if using the stick process. In some heavy industries welding efficiency is actually gauged by the ‘pounds’ of bead laid down in any given time period.

The whole advantage of a wire feed machine on chopper frame work is completely lost when one considers that most frame welds are only a few inches long and usually won’t consume even one electrode to begin with so don’t be fooled into believing that a low-cost wire-feed machine is in any way superior to an old stick-welding rig for work being done on thick wall tubing.

One of the problems with conventional stick and wire feed arc welding is that during the process of welding metals various gases are released from the solids as they melt. In addition gases in the atmosphere come in contact with the molten pool of material that lies just under the arc. These gases and impurities contained in the steel (or other materials) will contaminate the molten material in the weld pool, which can result in the weld itself being very weak in comparison to the adjoining material.

To keep the weld pool, the molten puddle of melted material, free of contaminants a flux is typically used. Flux is nothing more than a chemical compound specifically designed to trap and absorb impurities and to lock out external gases from the atmosphere. As the weld cools these impurities, held in check by the flux, form a ‘crust’ or ‘shell’ over the weld typically called ‘slag’. This slag itself is an impurity and has to be cleaned off with a wire brush before further welding or even painting can take place.

On a conventional stick electrode the flux comes from the factory as a solid chalk-like coating on the outside of the welding rod. On wire feed electrode the flux is actually contained inside the hollow welding wire and is almost invisible to the naked eye.

One of the problems with using solid fluxes is that during the welding process the action of melting metals and interaction of various good and bad gases create ‘turbulence’ within the arc that results in miniature explosions forcing molten material to be ‘splattered’ around the weld bead. An additional problem is that despite the use of solid flux a tremendous amount of impurities and gases, in the form of bubbles, are still trapped within the cooling weld so its not as strong as it could potentially be.

To counteract the disadvantages of solid (or liquid) fluxes welding engineers eventually developed what used to be generically called heli-arc welding. First patented in 1941 this process involved ‘flowing’ a stream of inert gas, in this case Helium, over the area to be welded. Within this ‘bubble’ of inert gas chemical reactions are greatly reduced and the cooled weld is relatively free of gas pockets and impurities. In addition the weld bead itself is very smooth and slag free and the surrounding area is not affected by splatter.

Heli-arc is still around but for most bike work the method used today is typically called ‘Mig’, standing for ‘Metal Inert Gas’.

 

Mig Welding

Most Mig welders are identical to regular wire feed welders except they use an accessory high-pressure gas bottle, pressure regulator also called a flow-meter, and a special combination wire/gas feed tube that extends to the handset. In fact almost all low cost wire feed welders are designed to be easily converted to Mig by purchasing a small accessory package and renting a bottle for the shielding gas.

There are some structural advantages to using Mig over regular stick or wire feed welding techniques if the operator is actually a professional welder but for the vast majority of us part-time welders the main benefit of Mig over other methods is largely cosmetic. The typical Mig weld is relatively smooth and the area immediately surrounding the weld is not as affected by splatter or spatter. There is no, or at least very little slag to clean up and in general the weld bead itself is fairly attractive and can be left undressed and simply primed prior to painting in an industrial setting.

 

Tig Welding

The term ‘Tig’ is an acronym for Tungsten Inert Gas and unlike all other forms of welding the ‘electrode’ is not consumed by the heat of the arc but acts instead as a steady source of the electrical ‘short’. The tungsten electrode has an extremely high melting point, usually higher than that of the materials being joined and for this reason under normal circumstances the heat of the arc will never consume it but in reality it is eaten away slowly and needs to be periodically dressed or ‘sharpened’. Like Mig, the Tig process uses shielding gases to protect the weld pool.

The biggest advantage of using Tig over Mig is that the Tig process allows the user to have almost infinite control over both the size of the arc and the amount of heat being directed into the weld pool. A skilled operator can weld tin foil with a Tig welder and for this reason Tig is the method of choice in shops that do both frame and body work.

By changing the size of the tungsten electrode and selecting different amperage ranges on the welding machine a Tig rig can accomplish almost any task that one would normally encounter when building motorcycles and motorcycle accessories.

In the hands of a skilled welder the Tig process probably produces the strongest welds possible in two pieces of material while adding the least amount of unnecessary heat into the areas immediately surrounding the weld. Tig welding was specifically developed for the purposes of doing precision welding as opposed to general welding. Tig welding is admirably suited to doing very fine sheet metal work and thin walled tubing frame fabrication but it is generally unsuitable for welding together large components like 1/2” thick motor mount plates.

The biggest disadvantage of Tig however is that because the arc is generally ‘cooler’ the process of welding is usually slower and requires far greater operator skill to obtain good deep penetration. Additionally since the Tig arc is generally smaller and more focused it is far more important that the fit-up in the pieces be as perfect as possible.

To bring this point home we watched two average welders working on the same type of chassis. One guy was using Mig and one was using Tig and it took the Tig welder twice as long to finish the same type of welds. From an appearance standpoint the Tig beads were outstanding, ready to prime without any further work being required but it took an awfully long time to do. In addition the Tig welder had to skip a few places where the tube fit-ups weren’t to good and go back over them with Mig to finish up. We had each welder give us a sample tube connection that we sawed in half on the bandsaw. The Tig welds did not have 100% complete penetration in .120-wall tubing along the entire length of the connections. In places it penetrated on average about 75 to 80% in depth but the Mig welds consistently went all the way through and were almost as clean as the Tig welds.

While this doesn’t prove anything it does at least point out the fact that Tig welding is in no way superior to Mig or even stick welding in the hands of average welders working under normal shop conditions on thick wall tubing projects. This fact is lost on experts who don’t seem to understand that the operator is as much a part of the quality equation as the process being used.

 

Theory verses Reality

No doubt you’ve seen a thousand posts at various cycle discussion boards spouting the pros and cons of a dozen different welding methods and another dozen techniques for specific applications. Most of these posts originate with welders who are skilled in one particular area of application or style themselves as a general expert in the welding field.

I personally think from what I’ve seen that many of the posts are from people who don’t do any real welding in the first place. That’s not to say that there aren’t good professional welders adding to the discussions as well. You just have to sift through to find the good stuff. There are some very good welders out there trying to help others learn the trade and you’ll usually find a link to their site or at least an email address on our links page to people who really know what they’re doing.

Welding up a chopper frame isn’t rocket science. Chopper frames need to be strong due to their inherent lack of good triangulation and are hopefully made from tubing that is thicker than 0.095 inch, preferably 0.120 inch and on critical tubes as thick as 0.156 inch.

For this reason almost any welding method capable of providing deep penetration in thick-wall tube is suitable and appropriate. Very Highly skilled welders can produce good results using Tig. Highly skilled welders can produce good results using Mig or regular wire feed techniques. For the vast majority of us occasional fabricators however conventional stick welding will most likely produce the strongest and safest frames we can build relative to our individual skill level.

Will there be a difference in the strength of the welds produced by the methods and skill levels of those mentioned above? The answer is probably not. Chopper frames built of mild steel tubing will usually fold up like a pretzel long before the welds break on impact even if a relatively semi-skilled amateur did those welds. Ironically the wheel rims themselves are the weak link in a cycle as far as strength goes. We have to constantly remember to separate theory from reality again. In the real world there are literally millions of pretty sorry looking motorcycle frames running around everyday of the week. You’ve no doubt seen a few yourselves. The welds on these bikes were obviously done by rank amateurs and in some cases, obviously drunken rank amateurs yet they somehow manage not to self-destruct when they hit a pothole. Then there are also the millions of bikes out there built by customizing professionals and the big factories between 1936 and up until the early eighties that were all stick welded. These are still on the roads as well and haven’t broken up yet. How come?

With the exception of the steering neck connection most welded connections on a typical chopper frame are not really in areas of high stress and in fact the typical frame with about thirty feet of tubing only has around ten structural welds with a total connection length of only three feet so that road and/or impact loads are well distributed over large uninterrupted runs of tubing before they arrive at any particular weld connection and in a properly designed frame none of these welds will be subjected to bending loads. To over simplify but to bring the point home lets just say that when you hit a bump in the road very little of that shock is directly transmitted or applied exactly on one of the weld points. This is why a poorly executed weld that has at the best only 1/4th the strength of the tube steel around it miraculously holds up under a full load impact event that will actually bend the adjoining rail. In addition tubular butt-welded connections as found on cycle frames are a whole hell of a lot stronger than a butt weld done on steel plates or angles. As load is applied to one side of a tubing connection the entire tube and not just the weld resists the load. As the tube tries to break the weld on the tension side of the impact it is also being pushed down into the solid wall of the adjoining tube on the compression side. This is one reason it is so hard to destroy a tubular connection with a sledgehammer compared to destroying welds in butt-welded angle iron for instance. To a huge extend the shape and size of the joined structural members determines the overall strength of a connection and not just the characteristics of the weld bead itself. The only exceptions to this fact are welds subjected to pressure stresses like process piping and pressure vessels of various types.

The steering neck connection is another matter entirely as it is usually just hanging out there in space and almost all loads from the forks are directly transmitted into the welds at the head connection joints.

The welds at this point in the frame must be as near perfect as possible, having good deep penetration with nice full fillets and reinforced with gussets if at all possible. Necks are hard to weld well because we’re usually dealing with two different sizes of tubing and each one has a different wall thickness. If the neckpiece is a machined component it may even be a different alloy than the 1018 or 1020 mild steel of the frame tubes. If you are at all in doubt about your skills have the neck welded on by a professional.

If you’re just starting out I’d like to reassure you that learning to weld is not as hard as a lot of people would like you to imagine. The learning process involves a lot of practice but it also involves a lot of reading and study, I urge you to read everything you can possibly find on the subject and to apply what you’re reading to your hands-on practice sessions. Don’t be afraid to experiment, at least while you’re practicing. Find a welder or an instructor to get you off on the right foot with a good foundation. Don’t be discouraged if it takes a while to perfect your skill as welding does take a certain amount of natural talent and manual dexterity. If it looks like you may not have such natural talent you may never be an expert welder but with enough practice you can become a good welder.

Remember that there are a lot of professional bike builders who don’t do any welding at all. As you’re starting out please don’t make the mistake of buying some cheap imported welder thinking it will be able to do good frame fabrication work. This is like flushing money down the toilet.

As was mentioned earlier Lincoln, Hobart and Miller all make excellent equipment and in addition they provide a wealth of printed and on-line technical and education material that is being constantly updated. Please visit their websites and spend a few days reviewing their respective equipment recommendations and associated technical literature. Bear in mind however that these companies are first of all in the business to sell equipment and only secondarily to educate welders so they do have a tendency to push the latest and greatest gadgets and/or their most profitable rigs.

Here at the old homestead we have an early model of the little Lincoln SP100 Mig welder, a newer Lincoln SP135, and a Miller-matic 135. All these of these machines run on regular 115/120V house current; we also have a Lincoln Invertec V160 220V Tig machine and an AC/DC Lincoln Buzz-Box. In my opinion the old Buzz-Box is the most versatile with the Invertec coming in second but we occasionally also rig up the Buzz-Box to run a Tig handset as well. These old Buzz-Boxes have been around a very long time and are pretty close to being indestructible so you can often pick them used at a very good price.

If I could only have one welder for the rest of my life it would be the Buzz-Box and at just under $500 new at most outlets it’s a bargain for the capabilities you get.

First of all this machine has the power to weld up virtually anything you’ll ever come across in DC stick mode up to and including solid 5/8” thick plates. It will also weld stainless and for sheet metal work we run the Tig handset. Electrodes are available for cast iron, stainless, and of course mild steel. If you use 7018 rod this machine can produce welds every bit as pretty as using a straight Tig rig and these welds will have a tensile strength of 70,000 pounds per square inch or about twice the strength of mild steel tubing. This is just my personal opinion so I wanted to find out what the real experts on welding had to say about machines, techniques and processes.

The real experts on welding are not the engineers, designers and trainers working at the big three but instead are the small engineering companies who specialize in examining weld failures. They see it all and what they report is not clouded in secrecy and there is plenty of info out there to be researched.

I was surprised to find, first of all, that the manufacturer with the greatest reported number of both weld and frame failures is Honda who ironically uses more robotic welding than any other builder. The only conclusion I can draw from this is that humans, despite their weaknesses, may be superior to machines.

I was not surprised to find however that the single greatest cause for weld failures is simply subjecting the weld to loads that exceed the design capacity of the structure that failed. In other words the weld failed because the entire structure failed due to overloading. For example bikes are not designed to be run over by trucks and stay in one piece. Hitting a pothole at 80 mph however should be within the frames design parameters. Improper structural design of the frame and connections results in more failures than poor welding techniques on their own.

Next down the list were weld failures due to what are commonly called ‘stress cracks’ or ‘fatigue cracks’ which occur over long periods of time where continual minor overloading of a connection, usually due to vibration, opens up an existing imperfection in the weld or nearby metal that increases in size and severity over time. It is important to know that not all fatigue cracks will cause total failure of a weld. I wouldn’t want to see one on my bike however. Fortunately fatigue cracks occur most commonly in brittle metal alloys such as chromo, stainless and 1026 DOM and are more of a problem in thin-wall tubing rather than thick-walled mild steel alloys. The large diameter thick-wall tubing that most modern custom choppers are made from is very resistant to fatigue failures compared to smaller diameter thin-walled frames as seen on street bikes and racers.

Since this isn’t a textbook about welding I think that we’ve at least covered the most rudimentary basics that you see tossed around the chat rooms and we’ve listed links in the reference pages to several equipment manufacturers and welding sites. We urge the reader to study any and all information at his or her disposal but to remember that welding thick-walled chopper frame tubing is not as terribly complex as many would want you to believe. It can be done successfully by almost anybody once the necessary skills are acquired regardless of the equipment that may be available.

Just remember that it’s vitally important to learn how to weld properly ‘before’ you start working on the chassis since a cycle frame isn’t something that you should be ‘practicing’ on for a welding class. If you’re not 100% confident in your welding skills just tack the frame together and have a professional finish it up.

Always keep in mind that the vast majority of good skilled chopper builders around the country can’t weld very well themselves. There is far more to building frames than just the welding aspects and learning how to properly cope and fit tubing is actually harder to master than learning how to weld. Build upon the strengths and natural talents you do have and get as far as you possibly can and where you run up against a wall find somebody to supplement your skills to keep the project moving. Making a commitment to mastering the art of welding is a long-term deal and not something to be taken lightly and certainly not something that can be based upon just having a desire to build a single bike frame.

 

 

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