This discussion is grouped around some of the techniques used to successfully produce items used in the adaptation of various systems to the user’s best enjoyment.
Our immediate area of interest is that of motorcycles, although as you will soon see, these skills can be used in a wide variety of applications sometimes in ways you have never yet imagined.
This overview is intended to give a beginner a basic list of tools, supplies, and sources of information to allow them to adapt various components to their uses. The refinement of these skills and expansion of the tools that can be used is something that can be a tremendous source of satisfaction and aggravation (sometimes at the same time). There is nothing novel or complicated being demonstrated here. Rather it is a return to skills that are rapidly disappearing. This is the basis of craftsmanship.
An important note about shop safety. Just because you are working with a hand drill instead of a drill press or milling machine doesn’t mean safety issues are reduced. Eye injuries are incredibly easy to incur as the relative hardness difference between a piece of steel and the eyeball can become painfully apparent. Conney Safety here in Madison has been kind enough to provide complimentary safety glasses and a catalog of their safety-related products. Among the items we would recommend would be eye protection, obviously, but also hearing protectors and dust masks. Once you attain the status of powered grinding, hearing protection is a must and if you are married, an occasional luxury. One of the major downfalls of the chopper shows is the habitual ignorance of basic shop safety procedures. Poking your eye out is not only painful but it delays completion of the project.
I have broken this potentially overwhelming range of information into segments that will deal with the basic elements needed to achieve results. The level of complexity and the tool requirements are intended to be within the realm of the well-equipped enthusiast.
1.) WELDING
This is the technique used to join parts together, and while scientific in its approach, it becomes artistic in its execution. While possibly beyond the immediate scope of a beginner, understanding the processes and their characteristics will make a better builder.
There are five common techniques used in welding metals:
A.) Stick Welding
This uses a power source and flux-covered consumable electrodes. While capable of high strength welds, it is best left to iron workers and is rarely used in any type of light vehicle repair or construction.
B.) Spot Welding
This is a type of forge welding where the two overlapping pieces of sheet metal are pressed together by the electrodes and an electric current is passed through them. The area of contact is melted and the sheets are joined. This is a type of welding found commonly in items largely constructed of sheet metal such as appliances, and passenger car chassis. It can produce the spectacular sparking seen on TV commercials, and is often controlled robotically.
C.) Torch welding or brazing
This is one of the oldest types of welding pre-dated only by forge welding. The most common type of torch welding involves an Oxy-Acetylene rig with pressure regulators, changeable torch tips and tanks. In a variation of the tip configuration, it also can be used to heat for shaping and to cut. This is how most welding was done until the advent of electricity. It is a slower, more easily controlled process that requires relatively little in the way of initial costs and does not require any special wiring or plumbing. Early aircraft were all welded using this method and some incredible examples of expertise can be seen at the EAA shows. The flame of the torch provides both heat and shielding from the atmosphere with filler rod often added. Many people have torch rigs lying around, but older ones need to be inspected for proper regulator operation and leaks as a leak at the wrong time or place will make for a rather exciting time with the neighbors, as a fireball will always get everyone’s attention!
D.) MIG welding (GMAW)
This process uses wire (as a consumable electrode) on a spool fed through a gun that also dispenses the shielding gas to protect the weld from oxidation. Most of the continuous welds you see are of this type. Most common are those welds on trailers, tubular furniture, railings, stock car and motorcycle frames. The high speed of the welding process and the ease of adjustment of the MIG setup to a specific weldment makes it a popular choice for production. The speed comes at a price, however. Control of the weld puddle in both location and depth makes precise weld quality more difficult on non-production applications.
E.) TIG welding (GTAW)
This is the bomb! Originally developed in the 1930’s, the use of helium as the shielding gas at that time gave rise to its more common name, “Heliarc”. This process uses a non-consumable electrode in a torch to melt the base metals with the shielding done by inert gas. A filler material is usually added. The control of this type of welding make is somewhat akin to writing with a 3,000 degree pencil. This is my personal preference for welding as the versatility allows the welding of steel, pot metal and aluminum with only changes in current, polarity, and filler metal being needed. You can be welding .049” wall moly tubing and within 15 minutes be set up and welding ½” aluminum plate. Hobbyist (non-commercial) TIG setups can be had for $1500 to $2500, while a Miller Synchrowave such as ours will run in excess of $6800 by the time all the extra features are added.
Now that you can join all the parts together, we can look at what you may weld.
(I.) TUBING CONSTRUCTION
This area is one of my personal favorites. It is like working with an Erector Set that can go over 200mph.
First, the difference between tube and pipe. Tubing is generally thin-wall (.250” or less) and is measured by its Outside Diameter (O.D.). Pipe is conventionally measure by its Inside Diameter (I.D.) and the walls are thicker. The exception to the tube rule is when exhaust applications are specified (and only by some suppliers). I have bought 1-3/4” exhaust mandrel bends, called “Tube” by two different suppliers that slid inside each other.
The various areas of tubing construction encompass fairing and body mounting systems,swingarms, exhaust systems, and of course the frame itself.
While a lot of places may use tubing notchers, the prototype characteristics of our operations make it faster to cut and fishmouth the tubing by hand. A chop saw is used to 
rough in the part, a bench grinder then provides the roughfishmouth, with the final fitting done with hand files. An assortment of files can be seen in the display. A couple different sizes each of the rat-tail round files, half round, and single-cut mill files are a good place to start. You will be surprised where else these will come in handy. Always keep the files clean and dry. If a chop saw isn’t available, a good hacksaw with adjustable tension and a number of GOOD hacksaw blades will work very well. The 59 cent cheapie blades are a great way to annoyyourself, make a good job look bad, and take at least twice as long.
When fitting tubing pieces to each other, the tighter the gap at the joint the better. Big gaps mean more filler rod, more heat, more distortion and less joy. A rule of thumb is to not have the gap more than half the thickness of the wall of the tubing.
Bending smaller diameter, thicker wall tubing can be done with a common conduit bender. While not elegant, it is simple and quick. The larger diameter tubing, especially where the thinner walls require more control is best done on a for-real tubing bender. These generally will use two to three shoes (or dies) and use both manual and hydraulic power to do the bending. An incredible amount of scrap can be produced with either one of these, so measure twice (or more) and bend once as unbending 4130 moly tubing is not advised. Trying to avoid a piece of that tubing flying out of the bender is like trying to outrun a cruise missile. I have experienced dents in the walls and myself when verifying this fact.
There are fewer more satisfying occurrences than taking a frame out of the jig, having the parts fit properly and actually have the thing do what it is supposed to, whether it is run through the ¼ mile (in its own lane), successfully negotiate the carousel at Road America or impress the crowd with its cool.
References:
Basic Oxy-Acetylene Welding, Cutting, and Heating Practices by L-TEC Welding and Cutting systems
Welding Essentials: Questions and Answers by William Galvery and Frank Marlow
Welder’s Handbook by Richard Finch and Tom Monroe
2.) FASTENERS
Now that the basics of providing a framework upon which to hang parts has been explored, the proper devices for hanging more bits or the original ones should be mentioned.
A.) Fastener Materials
Fasteners come in a myriad of sizes, types and materials. For the sake of simplicity, the most common types will be discussed here.
The most common fastener material is steel. Steel can have a very wide range of strengths, thus the need for grading of fasteners as a means of indicating the amount of force a fastener can exert before deformation and/or failure. The strength rating is generally stamped or forged into the head of the fastener and due to a major problem with counterfeit bolts a number of years ago, the manufacturer’s mark is also included.
U.S. fasteners are generally rated in a simple numerical system starting with a grade 2.
This fastener has no markings except for a manufacturer’s mark. These are generally used for extremely low stress applications such as windowscreens.
US Grades 5 and 8 are the most commonly used grades in general repair. Higher grades such as 12 are less common, and generally considerably more expensive. A properly sized grade 8 fastener will most often provide the best balance between strength, ductility and cost. These grade 8 fasteners are identified by six lines arranged in a radial pattern. A grade 5 will have 3 lines, and so on.
Metric fasteners which are becoming the norm also use a grading system, but not the same numbers as the US. The cheapest fasteners have no marks, just as the US, and are very weak. We do not recommend use of a non-graded metric fastener for anything but decoration. The progression of numbers is roughly that of the US counterparts, but 2 numbers higher. For example a bolt with a 7 on its head is roughly equivalent to a grade 5. The 10.9 rating is about a grade 8 and the more recently introduced 8.8 is in between.
We always spec an 8.8 minimum rating on replacement hardware with the preference going to 10.9.
When it comes to nuts and washers, don’t skimp! The general rule of thumb is to use a nut that is the same rating as the bolt or one grade lower. These nuts are harder to identify as the surfaces needed to stamp or forge are either being mashed by the washer or the wrench. The graded US nuts will have circular lines on the washer surfaces, the metric stuff is up to the vendor to properly identify. In the matter of washers, I don’t know a dependable supplier of hardened metric washers. Most of the washers sold are Grade 2. This is fine if there is little or no clamping force required as they mash to the shape of everything around them. You’ve seen these washers everywhere and how poorly they work. We use a Grade 8 (US) washer whenever possible. The plating isn’t shiny, but they stand up to the clamping forces applied (within reason). These washers can be identified by a maker’s mark stamped into them and the price as they are damned expensive! Washers are made in USS and SAE configurations depending on whether you want a large outside diameter or something smaller.
So far the discussion has been about steel, but the quest for lightness has produced fasteners made from aluminum, titanium, and plastic among others. Think twice before using these alternatives as their strength (except titanium) is less and their cost is more.
Aluminum could be used to hold on engine side covers with tremendous weight savings but care needs to be used there as they are generally only good for three or four careful removal and installations. Using a different color here than in the steel parts is a good idea to remind the person working on them what they are and reduce the likelihood of stretching or breaking every bolt during installation. You might impress the chicks with the ability to wring the head off of a bolt, but you know someone else is gonna be pissed.
B.) Types
The difference in fasteners is most readily seen in the different types of heads used. The types of head descriptions apply to metric and US fasteners alike.
1.) Hex head: This is pretty self explanatory
2.) Allen head: Also called a socket head cap screw, it has an internal hex drive surface. Often used in engine assembly, it allows a smaller head diameter and less room needed around the fastener for tight spaces. With extra machining it can be the lightest of the higher-torque fasteners.
3.) Counter-sunk Allen head: This is used where clearances do not allow the head of the fastener to protrude above the mounting surface.
4.) Button head Allen: Looking like a rivet, this fastener allows a reduced head height fastener and a larger bearing surface. This fastener is often seen holding on fairings.
5.) Phillips head screw: A screw with the readily identifiable cross pattern in it, it has been used seemingly forever to hold on engine side covers and when not removed with an impact screwdriver, necessitated a drill or a trip to a shop for removal. This configuration of fastener has probably widened the vocabularies of more people than any other single fastener type.
6.) Torx fastener (including tamper-proof): This is one of the newest additions to the head type used in everything from fuel injectors to restroom stalls. The extra area and drive angle allows for higher torque values and reduces the tendency to round out as can happen with allen head screws.
Other methods of attaching parts and panels exist in the form of quick-release (Dzus-type) quarter-turn fasteners and conventional fasteners screwed into riv-nuts. These methods allow rapid release and blind-side access. These are generally moderate strength or clamping force applications such as body panels and component mounts.
References:
Carroll Smith’s Nuts, Bolts, Fasteners and Plumbing Handbook by Carroll Smith
Engineer to Win by Carroll Smith
3.) SHEET METAL
This is an area of customizing and fabrication that has received more attention lately than any other in the form of the chopper shows on television. I am amazed by the skills of the truly great sheet metal artists, known as panel beater. Some of the better-known ones are BoydCoddington, Ron Covell, James Detulio (known as “Puppet”) and of course Jesse James. The unfortunate thing is that it is such a labor-intensive area that the best-known masters of it don’t have time to do it anymore. This area of creativity took its modern shape with the medieval armorers working for the knights.
I feel that personally panel-beating is one of my weakest areas, but I have been studying and abusing sheet metal of one type or another for over 25 years and have recently been rounding up tools needed to improve command of that discipline. I refer you to the videos by Covell and the sourcebooks listed for the widest range of education.
Basic sheet metal work will involve rudimentary hand tools as shown. For deeply-drawn shapes a torch will be needed to anneal the metal after the initial forming. Annealing removes the work-hardening that occurs as part of the hammering process.
A panel-beater’s sandbag and a set of hammers is a must, with dollies of various shapes helping in shaping process. As you can see, the possibilities are very diverse.
Different shapes can be made and incorporated into the designs of existing tanks as can be seen with the VTX, or a tank can be cut, split, re-floored and fitted as with the Bimota.
Breather tanks, fuel cells and airboxes are the most common use of sheet metal skills in a racing-oriented shop. Stiffening the panels is done with the bead-roller.
Once again, though, a previous discipline comes into play with the use of welding and torch techniques to expedite and finish a project in this area when it’s time to join the parts together.
References:
Sheet Metal Handbook by Ron & Sue Fournier
Metal Fabricator’s Handbook by Ron Fournier
4.) BRACKETS
This subject gets its own little space because while it is a physically small part, a bracket can provide great joy in its beauty and function or tremendous agony when it fails and whatever it was holding falls off.
There are basically two types of brackets: the clamping type and the connecting type. Sometimes these types are used together, occasionally in interesting ways.
The clamping bracket is generally one that wraps around a tube or pipe and attaches an object. These are made from either thinner gauge metal or machined from billet. The aircraft “P” clamp is a common application of the sheet metal clamp, while a Nitrous bottle bracket is a distinctive example of the billet variety. Each has its advantages and cautions.
The “P” clamp is relatively easy to make and versatile. It should only be used to hang objects vertically if possible as it can rotate on the tube.
The billet clamp has much greater clamping force available. It is more involved to make and thus more expensive. Its design is sometimes a limiting factor in its application unless you make your own. The greater clamping force mentioned before can be a problem in that it can pinch tubing, putting potentially dangerous stress risers in the tube, thus weakening it.
The “Connecting Bracket” is just that. It connects one object to another, whether it is hanging an exhaust, a turnsignal, gas tank, etc. Some of these brackets are shown. One of the more unique types is the rubber isolator type often seen on Harleys. These allow the isolation of the object from its mounting base. This is extremely critical with vibration-sensitive items such as computers, lighting units and thin sheet metal components such as fenders and gas tanks. These isolators generally will attach to a tab and hold off the object.
The link-type bracket can be made from steel or aluminum generally in the .080” to .190” thick material range. Very often holes and even patterns can be incorporated into the bracket for lightness and at the same time impart a “trick” appearance. Such a bracket is evident on the back of the Bimota holding the license plate. All the holes were done by hand with files and a die grinder. Just be certain the holes don’t compromise the strength of the part.
Using a cardboard template when designing the brackets can help insure they are right at least on the second try. Light gauge cardboard found at school supply areas works nicely for this and can allow the direct transfer of dimensions and hole locations from drawings or rubbings of the piece it is being fitted to.
When bending or forming the brackets also be careful that no marks or scoring occurs in the bend area or it will give a fatigue crack a perfect place to start. These marks can generally be smoothed away by hand or with a Dremel-type tool.
As mentioned before, sharp files and drill bits are a must to keep from making a nice project into a major affair. Rat-tail, half-round and single-cut mill files are the weapons of choice. When filing aluminum, a file card is handy to clean out the teeth of the files.
A bit of beeswax applied to the file teeth will also help keep the files from plugging up. You will have to remember to remove this wax before painting or disaster will result.
Drilling is aided by using the proper drill bits and speeds. We generally use 118 degree or 132 degree split point screw machine drill bits. The difference between screw machine bits and standard (or jobber) length is the screw machine bits are about half as long. This makes for a stiffer drilling rig and a reduced purchase price. Generally the “Made in USA” category (or better) are a good idea unless you are drilling wood. Also don’t spin the drill as fast as it will go when drilling, especially the very hard or very soft materials. A variable-speed drill will allow you to sneak up on the speed where everything is happiest. Blue-tipped drill bits are not a badge of distinction! When drilling thin materials it is always a good idea to use a piece of wood as a backup where the hole is to pierce. This reduces the tendency for the material to climb up the drill bit or catch suddenly. Watching your bracket imitate a helicopter is bad, trying to catch it while in motion is even worse!
These seemingly small detail brackets can be a source of pride, even if they aren’t readily visible because you know what was done and you know it’s there! There were many brackets on the Top Fuelers andFunnycars I made that no one knew about until the vehicle was stripped for service, and got a chance to see them in the light of day again.
References:
The Metal Fabricator’s Handbook by Ron Fournier
5.) MACHINING PARTS
As a person’s interests expand and the scope of their abilities advance, machine tools will come into play more and more often. For example, in the fitting of different wheels and calipers, a drill press and file just won’t do.
The most commonly seen machine tools are the lathe and vertical mill (or milling/drilling machine). There are many uses for these and while they are still available used, the fact that nearly everything is manufactured on a machining center has stopped the purchase of new units for manufacturing. These surplus manufacturing units were the usual source of hobbyist machines.
The procedures used on these machines will be briefly demonstrated here, but for the scope of this clinic, I will refer you to the text list, and possibly MATC, if they even teach anything about dials and wheels (non-CNC machining) anymore.
References:
The Machinist’s Bedside Reader by Guy Lautard
6.) PAINT & BODY WORK
In the course of customizing, you will eventually have to cover up the tubing, sheet metal and brackets. This task falls to the area of paint and body.
In the process of repairing or modifying plastic bodywork, the most expedient venue is a properly matched structural adhesive system. The system we use here is the Duramixprocess. The proper adhesives are matched to the base materials using the tests recommended by the manufacturer. A special dispensing gun is used to hold the tubes of adhesive which is forced through a disposable mixing tip by manually applied pressure on the gun’s trigger. The shaping plastic and reinforcing mesh can be combined to produce repairs or modifications that are often stronger than the original part. Conventional body fillers and glazes can then be used over top of this system.
Painting used to be something that could be done by a motivated individual in his garage or basement. Unfortunately time has marched on and things are no longer as they were.
The technology and emission requirement changes over the last three to five years hasbasically moved the home use of a spraygun beyond the means of most individuals. The expense and danger of the products when used improperly makes for an immense risk both financially and physically. With clear coats approaching $260 per gallon and the danger ofisocyanate sensitization it becomes more apparent.
Aerosol cans used to apply paint products can produce decent results if basic prep and application techniques are used. The key to any successful paint job is the preparation, just like in welding. A good, solid, smooth surface allows the paint to layout. This is
especially important with aerosol paints as the mil thickness of the coat of paint is very thin. There simply isn’t much material to work with when it comes to wet sanding and buffing. I have seen some very nice aerosol jobs, but beyond frames and engine cases aspraygun/booth rig is definitely the way to go. We have a tech article on this area of effort as well.
7.) WIRING
This is an area that is often overlooked by some of the most competent builders. It is an issue addressed briefly in my rant on the website tech article “American Chopper Syndrome”.
We have had to become adept at wiring as a matter of survival. Few alternatives can be found to permit the reduction of extra wires in a racebike besides doing it yourself. We found the Japanese manufacturers wire gauges and terminations from 1970 to 1994 to be an admirable model and went about securing the tools and bulk connectors to allow us to copy them. We are now moving into the lighter-gauge wire and terminations used in the
modern (1996 up) areas, but there are so many different types of connectors, we are still trying to standardize that mess.
The kit shown is what we started with and expanded as we found new connectors needed.
It is still what goes to the racetrack in the spares box, as it allows a dependable repair to be quickly made. As a quick plug, we do sell these starter kits and stock the connectors.
This uses a “Molex” type connector with strain relief. The connector basically pinches the stripped wire in the inner part of the connector and the second set of wings are pinched onto, but generally not piercing the insulation to keep the wire from failing from fatigue or the strain of pulling on it. These connectors can be used in the easily recognizable bullet-style connector or in differing sizes grouped in a “Gang Plug”.
Most of the connectors you will recognize from your travels. One thing you won’t see here are the red, blue and yellow connectors found at the auto parts or hardware store. The only exception is for battery cable ends and that is only under duress. This type of connector is not suitable for motorcycle use as they are generally too bulky, have no strain relief and fall apart. When asked to repair wiring done up with these, it’s best to simply quote a replacement of that section of the harness with the right connectors.
Insulating your work should be done with shrink tubing. Just be careful when heating the tubing to get it to contract that you don’t set the whole damn thing on fire. A heat gun may be a good investment if you plan to do much heat shrink work (a heat gun is also great for warming up decals to ease their removal and keeping your coffee warm).
Electrical tape has always seemed to be used in the manner needed to insulate you from lightning. A couple of layers of tape is enough. It isn’t very abrasion resistant and when it gets warm starts to slip. If you need to use electrical tape, 3M brand, (33+) is readily available and very good quality.
A quick note about wiring the newer bikes with ECUs and fuel injection. These systems LOVE ground wires. If you plan to move the ECU, be certain that there are adequate grounds. Sometimes these systems like to talk to anything and can do some pretty amazing (weird) things. Be certain that the motor has a ground to the chassis, something often overlooked in the course of painting or powder coating (both of which are insulators). Of course be certain the negative of the battery grounds to both the chassis and motor. Improperly grounded starters can turn that little 16 gauge harness ground into a direct relative of the same nichrome wire used to launch model rockets, with nearly the same result!
8.) COMPOSITES
No discussion of a fabrication project can be complete around here without the mention of composites.
Composites are basically everything else not metal. They range from plastic to fiberglass tohoneycomb to everyone’s favorite, carbon fiber.
We will look at the cloth-based composites, as injected plastics I don’t do, and gluing and repair of plastics was covered in Paint & Body.
Cloth-based composites generally have many similarities in that a non-porous stranded fiber is surrounded by a catalyzed resin system.
The variations of cloth range from chopped fiberglass (in a boat) to single-strand carbon fiber as used in the Britten motorcycle.
Some of the cloth used:
Fiberglass: Probably the best-known, having been around for decades. It is generally used in either the chopped (random directional) or woven formats. The chopped variety generally blown out of a “chopper gun”, is reasonably strong, inexpensive to produce but HEAVY. Woven cloth is used in hand layup pieces and can be controlled in orientation, thickness and resin retention.
Kevlar: This has recently been incorporated into roadrace bodywork to impart a toughness to the part, not obtained with fiberglass or carbon fiber. Not usually found by itself, it isinterweaved with the other cloth materials to blend the characteristics of the base cloths. A common hybrid is the Kevlar-carbon fiber seen in the pieces on the wall.
Carbon Fiber: This is the stuff! Beautiful, strong, and light, it is what I find lust-inspiring. The depth and beauty of a carbon fiber panel is hard to equal. It is stiff in relation to its weight and using different weaves and fiber orientation, stiffness characteristics can be controlled. Often used in a single layer, parts made from this can be incredibly light, yet strong. The bodies on the Top Fuel Funnycars are made of carbon
Fiber as it is needed for its stiffness at 325 mph. Top Alcohol Funnycars, with terminal speeds of only 250mph can still use fiberglass, although the bodies are 20% heavier.
A carbon body can cost $13,000 while the fiberglass version is about $6500. As I mentioned earlier, John Britten used a spool of carbon fiber to build his famous bike. Winding off what he needed for each pieces he was able build two complete bikes from one spool while prototyping. Most of our in-house bodywork construction involves fiberglass and epoxy resins.
The glues used:
Epoxy Resin: This is the strongest, but not very flexible. If you crash, it will break.
Polyester Resin: Commonly found, it is reasonably strong, moderately flexible.
Vinyl Ester Resin: The most flexible of the resins, it is the choice of a lot of the bodywork and gas tank builders. It is also the most heat resistance.
Choices of resins need to be made according to demands being put on the parts being made. Choices of hardener ratios can provide results ranging from gooey three weeks later to the mixing cup melting and nearly in flames before being able to apply a bit of resin.
Reading up on this area is highly recommended and speaking with people familiar with the processes involved is a must!
Resources: www.johnrsweet.com www.uscomposites.com www.fiberglast.com
I hope you have found this a bit of help or at least moderately entertaining (beating out most of the television shows of late).
The joy of creating is one that almost approximates a time machine because once you’reimmersed in the process, time disappears.
I would like to thank Conney Safety, Madison Wis., Guy Bartz, Ed Key, WJ, Fred, Nick, Sam, and Leigh for their help in this literature and the presentation of the clinic.
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