Tank updated Gear Cases for Kyosho RF006 worm gear set

thingiverse

This gear drive goes well with the Tank Track 2 in, Tank suspension, body parts, electrical and other Tank items in my collection. It can also be used mounted to any rail for right angle gear reduction. Hey back at it again with the original tank. I've gained a lot of knowledge in the last three years about gear boxes, made some changes to the old gear box. Going over the original tank and redoing some things to make it better, lighter, cheaper, easier and stronger. Keeping the original looks and suspension the same, this new gear drive design has had a lot of luck with, and the Kyosho worm gear drive set has been proven to be indestructible (this is the gear set I used for the 38,800 RPM Traxxas brushless motors that melted the small bearings into the gear cases, see YouTube video on Tank Track 2in). This new design uses fewer 3D printed parts and is stronger than the old gear box. Using a pair of 6x15x5m sealed ball bearings for the worm gear and two 6x16x5m sealed bearings for the shaft (they don't make 16mm OD bearings, see below). My RF006 Kyosho gear sets have the bearing tab cut off the end, so I've included a spacer. The original gear should fit in the case without removing the bearing tab. (I downloaded a pair of .110" spacers for the gear with stock tab sticking out). Just make sure the worm wheel/axle is centered on the worm gear. The shorter spacer goes on the inside side of the gear. There is an access plate that uses two #4x1/4 flat head screws (just in case the set screw ever comes loose on the axle gear). Using a pair of 6-32x1-1/2" machine screws and nuts per side to go through the case and frame. Two #6x1/2 screws for the top frame, four #4x3/4 screws for the inner case and three screws per side #4x3/8 screws for the back plate and two #4x1/4 screws to hold the inner bearing that allows some shaft bearing adjustment. Drilling #6 screw through holes at .140" (#28), #4 screw through holes at .120" (#31), #6 thread holes at .1065" (#36) and the #4 thread holes at .086 (#44) on the flat and .093" (#42) through the layers to keep from splitting. Trimming the shaft bearing bores to fit with a utility knife. The Kyosho gear set is made for 6mm shaft and has a set screw to hold it. The Worm gear has 6mm input shaft for spur gear. The gear box allows use of spur gears up to 1.72" diameter gear, about a 70 tooth 48P max. Max tooth count total 90T 48P for both pinion and spur, minimum of 63T 48P total with the adjustable motor rail. A 60T-66T spur with a 20T pinion is great for tank with RS540 motors. The Kyosho high speed worm gear set has a 15 to 1 gear ratio, it is a 30 tooth wheel and a two turn worm. Printing the outer cases with raft and exterior support. Printing the inner cases and the parts without raft. I use 2 extra shells and 20% infill for the printed parts. Update: Downloaded the gear case covers to go with these gear boxes for the top of the frame. Using three #4 sheet metal screws per side. Made to use with the Sabertooth 2X12 in the middle. Sabertooth mount and cover are in a listing in my things and go with the old Tank body parts. Update: Downloaded some new gear cases with the number 15 on the end of file name. The cases were originally designed before I found 6mm shafts. My bearings were 1/4" ID, 5/8" OD and I just realized they don't make 16mm OD bearings for a 6mm shaft. So this new case is made for all the bearings to be 6x15x5, which are readily available along with 6mmx100mm shafts. Also a spacer for the one side of the worm gear as mine was cut off to use bigger axle. These new cases should solve any problems with the 6mm axles and bearings. Use the old cases if you drill out your worm to 1/4" shaft and use 1/4"x5/8" bearings.