New Blog, Building a 38U Flathead Motor

Starting a new thread, on the 38U I’m building this winter.

This is a jig I built to resize roller races. The pieces that are the actual jig are the round sleeve with the bolt(handle)welded to it which is an old sprocket bearing bush that I pressed out of the cases earlier.

The problem I was having was that the cages to contain the rollers for the pinion shaft bearing that V Twin currently sells aren’t sized properly. The rollers fit into the cages freely, but when you attempt to put the caged rollers over the shaft, the physically just won’t go. So, my bright idea was to put the cages with old rollers in them on an old an old sprocket shaft with 400 grit lapping compound. As the pinion cages are shorter than the sprocket shaft bush, i threw some extra stuff on the shaft to take up space. I put a hose clamp on the end of the shaft to keep it all together. i clamped the shaft in the lathe chuck and spun it at 200 rpm for a few minutes, till I could feel the resistance on the tool handle subside. Pulled out the pinion cages, cleaned, and inserted clean new rollers, and Voila! freely rolling rollers!

Above is a pic of components making up my sizing jig.

The round bush in the bottom of the picture is a used sprocket race from the U motor. On the right side of the picture is the miscellaneous “stuff” I put on the shaft to take up space so the rollers/cages wouldn’t separate inside the tool. I used the larger Sprocket bush just in case I might need to use the tool on some other cages someday.

Just a simple little jig, but it solved a problem I’d been having with Big Twin Flathead motors for several years. The supply of OEM cages has dried up, so i needed to come up with a solution.