Team 47... Alchemists...

[Joe Johnson]

The drill kit goes for about $180 with all the batteries, etc. I wish they would sell the drill alone, I think it would be cheaper than buying the parts I need.

The transmission is about $20, the bearing housing is about $30, the clamshell is about $15, the back of the housing is about $5 as I recall, the motor adaptor and misc. screws are about another $10, when you add in that you have to buy 1 transmission for every 4 gearboxes (to get the input pinions you need -- luckily the planets from stage 2 work as suns from stage 1, if not, we'd need to buy a motor too for each gearbox adding another $30 or so). So far I have about $85 into the gearbox.

The only thing left is $20 to wire EDM the hole in the planets to a press fit on the motor in question (.125 dia for the FP, .155 dia for the Globe, 4.98mm dia for the Bosch, .160 square for the seat motor, .312 dia for the Chiaphua, don't quote me, but these are appr. right). The reason that the hole has to be EDM'ed is that the planets are hard (really hard).

As to mounting, the aluminum clamp collar is about $17 (part #6436K151 from McMaster.com)

All you have left is to weld (or perhap bolt, though I'd recommend welding) the clamp collar to a bracket on your robot and you're done.

Well, not quite, you also have to drill and tap a 1/2-20 hole in a sprocket (we used a standard #35 sprocket with 8 teeth -- cheap $7), screw it on to the drill output shaft, make a small spacer, and put in your left hand screw to keep the sprocket from unscewing.

I figure the whole drive unit cost under $130 each. On a typical FIRST gearbox on a typical year, I would spend more than that just on the gears alone.

I think that this is going to be a huge success and that many many more teams will do this next year.

Look for a white paper after the season is over.

Joe J.