I have been committed to a trailer fender for this bike since the gestation. I have never used one, but always thought they were cool on the right bikes. I like that before there was a huge chopper aftermarket, this was one of only a handful of options for the home builder.
I stuck with stainless steel throughout the process, polishing it as I went. Fender, struts, bolts, etc. Many people ask why I use stainless steel instead of chrome, a good question. For me, the main reason is durability. Chrome is only a paper thin coating of metal, bonded to the surface of the base metal. While extremely hard, chrome has a tendency to flake off, especially "show chrome", the type used for cars and bikes. Stainless is not a coating, so it cant flake off.
The second reason is that chrome interferes with part fitment. When two parts have to interact (bolted together), I like metal-on metal contact, which means two perfectly flat surfaces against each other. I try to never have chrome, paint, or powder-coating between two parts. The reason is obvious; as the bike flexes and vibrates, the weaker material will break down and compress, leaving you with a loose connection.
Third is because chromers are, frankly, a pain in the ass. It costs a fortune to get a bikes worth of parts plated- far more than the cost of the raw material in stainless. It is not unusual to have a frame plated for $3000, and within a year all the welded areas are rusted. And the time factor too, weeks and weeks waiting, can be very frustrating. Its another sub-contractor, and another variable, that I don't need to deal with. There are good ones out there, but they are hard to find. I'm sticking with stainless.
What I decided to do was mount the fender using a flange at the back of the toptube, and two struts per side. The fender itself is 13 gauge stainless, and combined with the 6 mounting points, should be quite secure. Here is the flange, about halfway through the process of machining. Prior to this pic I was in the lathe. This part started out as a 6" long by 4" round solid chuck of steel.
The surface you see here is slightly concave, which matches the surface of the fender perfectly.
For the fender itself, my usual routine is to make bungs or tabs that the struts can attach to. These are usually welded to the sides of the fender. I thought that if they were actually one solid piece of round stock inserted through the fender, they would be far stronger, as well as perfectly symmetrical. This bike afforded me that possibility because I wanted the fender to be mounted high above the tire. This gave me the clearance I needed. Here is one protruding out through the fender side. I have tack welded it, and will do the final weld later.
The rods were milled out for the portion under the fender to increase tire clearance and save some weight.
What is the downside to stainless? It is hard as hell to work with! It is extremely hard on tools, warps like crazy when welded, is expensive, and hates to be formed in any way. If you want it shiny, or even a consistent matte finish, I spend hours prepping it. This can involve hand sanding, bench sanding with an orbital sander, using the Burr King heavy sander, or abrasive cutting compounds on the buffing machine.
Here are a few pics of the strut making process. They have been sanded to about 500 grit in this pic, and will be sanded more, then buffed:
This part was a bitch to get symmetrical- the top section of the front struts.
Here she is now. The fender isn't fully polished, because I still have to do the final weld around the rods. The strut sections have been polished piece by piece, because there will be no way to hold the entire assembly up to the buffer. The back of the seat will be attached to the front strut assembly.
strut to frame mounting
Next post- seat pan making....