Team 47... Alchemists...

[JAH]

That is really cool. I'm assuming you ordered the transmissions all as replacement parts from DeWalt and used them that way. I'm hoping you didn't buy 8 drills and take them apart! Seems really neat, and if I remember, I'll be stopping by your pit in Atlanta, since that is the only time Cyber Blue 234 will see you all. We even have one of those drills!

[Paul H]

Yep, Jim (Zondag) has one and was showing us one of those gearboxes that he has before the season, those things are nice.

[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.

[Joe Johnson]

One more thing, Ridgid Tool has a similar design in terms of the handle being a clamp on affair. They almost won my "Best Drill for use in a FIRST Robot" Award, but got edged out by 4 factors:

1. The distance from the clamp surface to the output shaft was lower on the Dewalt -- Torque = Force X Distance -- lower distance, lower torque on my mounting brackets.
2. Three speeds on the Dewalt vs. 2 on the Ridgid Tool drill (more options for ratios without having to bother with changing anything but a setting on a yellow housing).
3. The method Dewalt uses for shifting is more reliable than the method that Ridgid (or Bosch for that matter) uses. They planetary rings move axially just like in all the other, but the shifter works by rotating a camming device that is just plain gorgeous in its simplicity and reliability. I don't recommend it, but these babies can be shifted on the fly without the gearbox complaining at all hardly.
4. Finally, the Dewalt Service Network is AWESOME -- easy to order parts online, easy to get parts breakdowns, easy to find local dealers, etc. It is like they are designed to be FIRST friendly.

I am not an owner or stockholder of Dewalt, but I cannot say enough good things about them and this product.

I have already started pestering them to get to a FIRST competition (and to sponsor FIRST with drills next year ;-).

If anyone has any inside connections to Dewalt, give them a call and try to get them turned on to FIRST.

Joe J.

[JVN]

Random 229er: "You're obsolete"
Me: "Yes I am"

Joe... serious kudos are due.
I am seeing implications that will shake the entire FIRST design world.

I will DEFINITELY be interested in more details.


Poor Baker.

John