My DIY track ends
by Mike Perry
I have a history of converting old bikes to single speed. After I'd jury-rigged four or five with sliders, I decided it was time to try doing one the hard way. I found a dumpster bike, made a set of track ends, and welded them in place. I wound up with a nice winter bike for the woods.
In case I make all this sound too easy, I guess I should tell you that I teach auto mechanics at a school in Cambridge, MD, and I got some help from co-workers. Still, I believe that anyone with access to a basic machine shop and some means of welding could do a good job. Take it slowly, and don't be ashamed to ask for help from more experienced metalworkers.
The bike I chose for conversion was a 13" Trek. It rode nicely enough, but I knew it wouldn't break my heart if anything went wrong.
The first task was to make the track ends. I needed a big, flat plate to give the bike a strong, stiff rear end. (When you do your own work, you can make things exactly how you want.) I sketched shapes on card for a while until I had come up with a design I liked, then cut the card and traced the outline onto 1/4" plate steel. Next, I cut the plate with a torch, and cleaned the ends up with a grinder.
Now it was time to work on the frame. I was planning on using an old 110mm flip-flop hub, so I needed to respace the rear end. (It's easy enough to coldset steel, and with patience you can work on aluminum too.) After checking the alignment of the frame, I cut out the old vdrops with a hacksaw, and slid the new ones into place for a mockup.
The ends fit fine. In fact, they were tight enough that I had to tap them into place with a hammer--a good sign. I'd done pretty well so far, but from here on I would need some help.
First, I coopted a machinist friend to cut me an aluminum spacer from a cylindrical billet, and dug out a long bolt from the parts bin. This assembly would hold the ends in place during welding. Then I went to see the welding teacher at school, Ray O'Brien. Ray, who once welded for a Belfast shipbuilder, had promised to do the actual welding for me. Before taking the frame, I carefully cleaned all the paint off the ends with the grinder. Stray paint can contaminate a weld, weakening it, and I didn't want Ray to waste his time prepping.
Ray did a beautiful job with the TIG welder, and one check with the hub told me that the bike's new rear end was true.
I mixed up two shades of blue Deltron basecoat to match the Trek blue--close enough--then finished with cheap Kirker clear. I built it up with old-style BMX cruiser wheels, Sun No.5 Orange rims on high-flange, and some used cranks. The cranks were Specialized Hardrocks, actually a pair of rights, with the spider hacked off on the non-drive side. I had to flip the ring to get good chainline, but everything came together pretty well.
I keep meaning to put on a better finish--I sometimes do custom paint work in the booth at school--but somehow I enjoy the bike too much to get around to it. Meanwhile I'll keep riding. And I have plans for another bike. Cobbling your own frame is addictive...