Steed: Built to Ride

Billet, What Is It?

Tech Tip Index

It seems to me that I've been hearing the word 'Billet' used, misused and even abused over and over, which leads me to the conclusion that there's a lot of confusion about that 'Billet' word that people are using. O.K., what the heck is billet?

Let's go to the source, Mr. Webster says: billet (bil'it) n.1. a piece of firewood. 2. a wooden club. 3. a part of a belt strap that fits into a buckle.4. a small metal bar, often square."

I don't see much use for firewood on a bike, unless you're going camping. A wooden club might come in handy during a fit of road-rage, and there are belt straps on some Harley saddlebags, but I don't think that's what all the fuss or confusion is about. On a motorcycle, these folks must be talking about that 'metal bar, often square' that is, or isn't, either adorning, lusted for or scorned, never to be found on, or something to be boasting about that's bolted all over your bike.

The truth of the matter is that you can call a chunk of wood, steel, aluminum, brass or even plastic "billet". Billet is a generic term for a hunk of raw material that has been processed by removing materials to make the final part. Fact is, you can carve a bar of soap and call your masterpiece billet if you are really bored. This is where the confusion really sets in. I've seen "Billet Look" mirrors in catalogs. What the heck is Billet Look? I don't know exactly, but what it comes down to is that the process of producing a finished product out of a chunk of solid material, rather than melting and casting it, ends up looking just a little different.

Billet parts had a more substantial or squared off look, due to the machining process until the advent of 'modern' sophisticated CNC (Computer Numerically Controlled) milling machines. Even then, once the manufacturer has polished off all the milling (think carving) marks and possibly chrome plates the do-dad, there's no telling what process was ultimately used to produce the piece.

Now, in the wacky world of limited-quantity 'custom' motorcycle widgets, billet parts are usually more expensive than the comparable cast unit. This is due to the nature of billet machine production time, or 'run time' involved in making the part. Each billet thingie-ma-bob requires much more handling and time to cut individually, versus casting a large number of identical do-dads at one time. Sometimes the advantage to machining a billet part over casting comes right down to economic factors regarding the number to be produced. If you are running a small number, the financial choice of the manufacturer might be to use billet because of the enormous cost of making a mold to 'cast' the same widget. If the production runs into large quantities, sometimes it becomes more economical to cast the dew-hickey. Pretty technical jargon, huh?

Now that I've got you really confused, let me briefly explain casting, or the Die-Cast process. There's absolutely nothing wrong with die-cast parts, and there's a ton of them on your stock bike. Look at your handlebar controls, primary cover and the end covers on your cam, rocker boxes or transmission. All of these are die-cast parts that function quite well. Your engine case and transmission case are sand-cast, or investment cast, which is a similar process, but the molds are usually larger and not reusable. Either way the process to cast a piece involves melting the material, metal or plastic, and pouring it, or injecting it with pressure, into the mold, and then when it cools, voila', there's the goods. Sometimes cast pieces are then machined to add more detail, mating surfaces, threaded holes for mounting or attaching other parts and then all of a sudden the cast part starts to look like a billet one because of the machining process required to finish it.

So then you might ask, "Why is billet in such demand that is has created a new word that can be abused, misused and either loved or hated by bikers?"

Actually right now there is a little bit of a backlash in some circles that think billet parts are 'jewelry' or 'flagrant displays of excess spending' and don't belong on a 'Real' bike. There are parts that need to be made of billet due to the strength characteristics that 'billet' material has advantages over cast materials. Think of a piece of lumber cut from a tree as billet; it has grain and some strength and rigidity. Then compare a piece of particleboard thinking of it as die-cast; it has no grain direction, and lacks the properties needed for structural strength. I wouldn't want a cast axel on my bike, and that's just one example of a billet item that's on your machine, and for a real good reason. There's a bunch more.

Billet parts started appearing on motorcycles in the late 80's and early 90's due to the large number of machine shops that were building items for aircraft, space exploration and military projects. A bunch of these guys who owned machine shops ran out of contracts at that time, due to a sluggish economy, and started to make smaller number of 'custom' parts. Putting the machines that they originally bought to make the goods for Uncle Sam, building cool billet stuff for motorcycle fanatics. When you match this availability of talent and state-of-the-art wizardry to produce the billet gizmos, mated with the growing popularity of individualizing your bike, it was a match made in biker heaven. A bunch of these parts were purely cosmetic and replaced the die-cast original equipment parts, simply to just to get a unique or exotic look (here's a real tip: whiter teeth and fresh breath will always get the chicks). Wheels are the first thing that comes to mind, and there were a ton of billet wheels that just exploded into the market. Along with matching belt pulleys and matching brake rotor designs you can lose your mind and blow your whole budget on billet. Most of these spendy tire-holders were designed to replace the stock 'mag' or cast wheels. Billet Aluminum seemed to be the material of choice, but now you can get cast wheels that are machined to look like they were billet. Go figure?

Cast wheels are usually less expensive primarily because they require less time and material to manufacture than a billet wheel. Remember, the billet wheel was a huge 'square' solid piece of material when it started, so the design and open spaces, corners or holes, end up as little chips on the cutting room floor. Just like sawdust in the lumber mill. Most machine shops recycle the waste material machined off during production; otherwise they'd be buried in the scrap waste accumulated by machining billet parts. Regretfully these chips of waste material are not worth much as salvage scrap, pound for pound, unless you are machining a solid billet brick of pure gold.

Speaking of gold, soon excess became the word. By the late 90's billet parts for your Harley were everywhere and became a R.U.B. status symbol. This attention to detail, just like anything can be taken to the extreme, and thus the new breed of 'jewelry' bikes hit the road (or the trailer) occasionally sporting too much of a good thing. Lots of people are impressed with excess and not necessarily form and function, so right now extreme use of billet is getting frowned upon by many of the 'old school' chopper purists. Isn't it funny when untrendy becomes trendy and then becomes uncool only to become cool again? I say to each his own. There's no reason to bash billet, but there's not a lot of additional benefit to a cosmetic part if it's billet or die-cast.

Hopefully now you understand the basics of billet, and can make an informed decision regarding its use or abuse on your machine. Is it billet or isn't it?

If this isn't enough extra vital information to pack into your wind-blown brain, stop in and ask me what 'forged' means, and I'll do my best dazzle you with more minutiae.

Keep the rubber side down.
- John at Steeds

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