Drill Mount Suggestions?

Four our drive train we have decided to use both the CIM and the Drill motor, however we’ve decided we’d rather just use the motor and not the included gear box. Does anyone have any good ideas that they are/have implemented on a mounting syustem for just the motor part of the 1/2" drill motor? Thanks.


Are you going to make your own custom made gear boxs??

We have used these two motors together before and you cannot use the gear boxes they give you, obviously. Last year we just made our own gear box to match the RPMs and plan to do the same again this year.

there’s a white paper (maybe two) on combining these motors easily…

check out the white papers section for more info :slight_smile:


there is no easy way to join the two…unless you don’t care about how long your bosch motors last

That is what we did. We have a 2 speed transmission, and we used both motors and just made a custom made gear box for em.

you say u have a 2 speed tranny. can it switch gears reomtely on the fly? if so how do you acheive this?

i think “easily” was taken out of context…

i meant it wouldn’t take a lot of manpower…one whitepaper tells you how without having to have a fancy machine shop.


We are trying to do the same thing: use the drill motor w/o the gearbox.

I think that Ryan’s original question is concerning just how do we mount this drill motor if we are not using the gearbox… it’s not very straightforward.

I see two options:

  1. Use the two holes on the output face of the motor as pilot holes for a #10-32 or M5x0.7 tapped hole. If you were to do this, you would either need to use a metal forming tap instead of a cutting tap. Or, you just need to put grease on your cutting tap and go slowly through the hole… bit by bit… wiping off the grease and metal pieces for each turn or so… then putting grease back on the tap before cutting again.

The whole point of being careful, of course, is to not get metal shavings in the drill. Since the drill motor is worth $23, it’s worth taking your time to do this.

  1. Use the holes on the side of the motor. The same care would be needed when you tap these holes also, and they are in a non-convenient position. You would have to make a bracket (or 2) to get the motor mated into the gearbox, and that is kind of a waste. Also I don’t see a good way to insure the motor’s position when doing this.

I suggest option 1. We have not tried it yet, but we probably will within a few days. I’ll post again to let you know how it goes.

Andy B.

It took us all 6 weeks last year. We almost did not pull it off. We switch gears using a servo. The only problem was that once we were in High Gear we could no longer switch down and a few of the dowel pins kept on falling out. So what we are going to try to do this season is get rid of the servos and see if we can switch gears using the pneumatics and tack weld the dowel pins in so they do not fly out.

If you are going to use a servo to switch the drills, make sure that you have a strong interface between the servo arm and the shifting ring. Last year, we had problems when we just used stiff wire to connect the two. Basically, it could only push the arm into the neutral position before deforming. After we used a piece of metal to connect the two, everything worked fine.


Andy you got it more or less, I’ve already designed the gearbox for coupling the two to a common output, that wasnt the problem. My problem was actually mounting the drill motor without the front gearbox. If you can relay how the best way you found to do this after you try it, it would be greatly appreciated.

My white paper on our gearbox will come eventually, but not untill after 6 weeks :smiley:


-One day, I too will be a moderator on these boards…

we combined both the chiphua motor and last years drills together, they worked ok

it was kinda sketchy at first, but then it was ok…


Hint #1: Look carefully at the front of the Bosch motor, then examine the plastic motor retainer on the back of the stock Bosch gearbox. Notice the two round holes in the motor that fit over the two round pins on the gearbox, which prevent the motor from rotating when it is applying torque.

Hint #2: One the front and back of the Bosch motor, there are two ~1/4" square indentations, spaced 180 degrees apart. Seems like they are perfectly located for alignment/retention locks, doesn’t it?

Hint #3: Take a look at how the hold-down strap for your car battery works.

We are also going for the dual-motor, dual-speed transmission, updating our design from last year. Throwing away the Bosch gearbox, and just using the motor directly into the transmission saves about 2 pounds per side of the robot.


Steal from the best, and then invent the rest!

OK… we are in the final assembly of our gearboxes and we have had some success.

We took the drill motors and tapped the two holes on the face of the motor for a M5x0.7 screw.

Beginning with a regular tap dipped in grease, we started into the hole. Then, after a few turns to get the threads started, we pulled out that tap and began with another tap that had the point ground off of it (again, with grease). Using this tap, we threaded the hole deeper and got some pretty good threads on it.

The grease is used to grab the metal shavings when cutting the threads.

The motors were mounted into our gearbox and the threads seem to hold… we are not tightening the screws down too tight quite yet, though.

Also, we did this upside down. Clark and Kyle Gilbert performed this procedure… they may have more comments.

Andy B.