pic: NanoShifter

[Tom Ore]

Originally Posted by JesseK

I think this would be the best method, with standoffs located at the 4 pre-made holes on the corners of the extrusion. Of course, the thickness of the standoffs may interfere with my next topic...

The ratios do not appear to be that much different from each other with this gearbox. I presume this is due to sizing restrictions? 2 methods to deal with this are:

1.) Increase the diameter of the driven low-speed gear, which would then require slots in the housing and thin standoffs or no standoffs from the assembly method above.
2.) Decrease the diameter of the driven high-speed gear, which may require yet another custom gear for the dog gear to mate to.

Which brings up the question -- what is the smallest size 20DP gear that can be pocketed out for mating with the dog gear?

All the gears shown are custom. It looks like the standard shifter (AM-0001) was set up for 4" wheels. The 6" wheels cause some trouble with ratios.

The ratios shown are at about 8 and 12 fps. The high speed (12 fps) ratio could be made faster with no problem. The large output gear already interferes and would need a clearance cut in the housing as it is. 8 fps isn't too bad for mecanums anyway - wheel slip is around 9 fps so you don't get much benefit for going slower.