Monday, July 25, 2011
Custom bevel gear box
I have been doing more prep work on some of the remaining panels. However, the biggest update is that the gear box parts were complete, and I now have them assembled. The gearbox is similar to the recent custom boxes Rick has made. He uses pillow blocks for bearing mounts, and this allows for easy manual machining in his garage shop. I don't even have a drill press, so I knew I would be sending out these parts to a local job shop with CNC capability, and I designed a similar box with flange bearings. It requires some precision holes for the bearings, but most shops should be able to manage. The motivation is to get a box that should be able to hold up during a sprint, and that is fairly light weight, and has an efficient gear ratio without need for a chain to reduce further. The gear ratio is 4:1, higher than any stock gearbox available. It weighs in at 5.4 lbs including crank arms.
We had some machining hiccups and I also needed to fine tune the fit a little between a few pieces using sand paper, but overall the result looks really good. I think it should hold up really well.
Total time up to this point (just for the gearbox assembly): 5 hours.