Treads are tough!
Title says it all.
So I had some ideas rolling around in my head about how best to cut in the diamond crisscross tread pattern into these wheels. One thing I knew, I would make a computer drawn template to mark the interval of tread, since CAD does such an easy job of dividing (a lost art in machine work actually):
The template is included in my wheel update sheet for both nose and main wheel. That was the easy part, now how to actually cut in the treads? My first go around was to make this fixture. This is the “Cutter, Wheel Treads, Model M-1”:
This was made from 0.080” (2.0mm) styrene, glued with Testors liquid cement. Makes for a pretty rigid structure, and seemed like it should work. Used it first to draw in the lines to aid in cutting:
Then using a razor saw, tried to cut in the groves with the fixture as the guide:
Took awhile to get the technique down, which I figured is always the way. The first one of anything is always the trail blazer, and then it gets better. So I painted the wheel up to see how I did:
Not as good as I thought. Passable at best, but as can be seen, there were double cuts, off-interval cuts, etc. etc. I could see I had to iron out some issues with the fixture if I was to make a better tread. So, noodling it through last night and this morning, I cannibalized the first fixture to come up with a second generation one. Behold the “Cutter, Wheel Treads, Model M-1-A1”:
Easily the most elaborate and over engineered thing I’ve done for this project, but I figured if I can net all the errors from the first attempt, this will be a useful tool for many a future project. Some of the things this rig incorporates to overcome the problems I found in the first: Plate steel saw guide to keep the saw aligned and square, rubber pad at the base of the wheel mount to hold it firm when cutting, and the ability to shift the plane of the saw to the opposite angle using cradles:
I tried it on the first wheel and after a few messing around cuts, achieved a pretty straight cut:
The test is to see if that’s repeatable. The two pins in the foreground of the pics resulted in those first tentative trials. The metal saw guide wanted to jump out of its cradles as I sawed, so now I pin it into place at the sides.
Well it looks like I will have to sand/shape that third wheel, but I guess my sinuses will just have to suffer a bit more. Some more trials tonight with any last minute tweaking as required, then I should be able to crank out some treaded wheels…..yeah right!
Mike