Drill Motor Gear Specs?
 

Does anyone know the exact specs: Pitch diameter, pitch etc. for the gear that is on the Bosch drill motor. I am trying to make a gear reduction box for it (without the planetary reduction that comes with it) and I want to get the center to center distances right, and get the correct gear to mesh with it.
Near as I can measure the pitch seems to be 7mm but if anyone knows for sure - or where to find the info - I would much appreciate it.

Thanks,

Greg

Team 709

Re: Drill Motor Gear Specs?
 

Re: Drill Motor Gear Specs?
 

Bill, thanks much. Not to be ungrateful at all, but the pdf was a little hard to read...looks like somebody scanned it. Any clue where the manufacturer's site is or if anyone has a CAD file on it?

Thanks again,

Greg

Re: Drill Motor Gear Specs?
 

firstcadlibrary has one, but they seem to be down right now.
The pinion gear is a 15 tooth, modular 7 pitch gear. Pitch Diameter is 10.5mm and the gear has a 9mm face width if you couldn't read the posted pdf.
You can find gears to mate with it from PIC http://www.pic-design.com/
Also, a nice mm to inches converter can be found here http://www.omnis.demon.co.uk/

Re: Drill Motor Gear Specs?
 

Thanks Rob,

Do the gears change from different years? I downloaded a drillmotor gear from FIRST CAD but it has 12 teeth...like the one on the drillmotor I'm looking at right now.

Greg

Re: Drill Motor Gear Specs?
 

The motor & pinion posted on FirstCadLibrary are not from last year. I intend to post this motor & pinion very soon.

Re: Drill Motor Gear Specs?
 

Last year there was a new model bosch drill motor given in the kit. Previous years drills were from a 3/8 inch hand drill and last years were from a 1/2 inch. Every year the motors change up a little so its always good to be cautious when designing things pre-season.

Re: Drill Motor Gear Specs?
 

For those that have knocked the pinion off of the drill motor:

1) Do you have any idea how much force (in tons) it took approximately? I have a 1/2ton arbor but I'm not sure whether or not it will do the trick.

2)What did you use for the punch itself?


Thanks

-Rc

Re: Drill Motor Gear Specs?
 

I would not suggest taking that pinion gear off the Bosch. Doing so just adds about 10 things that can go wrong with it. The small metric gear on it now is press fit perfectly onto the small metric shaft. You can order mod7 gears from PIC to mate with it very nicely. In all, its just much more added complexity and time to save ordering 1 mod 7 gear.

Pinion Removal
 

We took the pinion off the motor and a 1/2 ton will work fine. We used an M3 bolt as our punch. Line in up and slowly press it off .. like butter.

To place another pinion on the shaft, I suggest a 0.001" to 0.0015" press fit maximum.

-Paul

Re: Drill Motor Gear Specs?
 

There is a 60 tooth mod .7 gear posted on the First Cad web site. I could not find this gear...I' sure it's out there I just couldn't find it with someone who could deliver it in less than 6 weeks. I actually tried to make it on a laser cutter but there was too much heat for that small a gear...I am thinking of trying it on a water jet cutter but I would love to just buy it. I will try PIC gears but does anyone have any other ideas. Also, does anyone know the pitch circle of that 60 tooth .7 module gear?

Thanks one and all,

Greg

Re: Drill Motor Gear Specs?
 

60 teeth x 0.7 = 42 mm pitch diameter

Good luck getting parts delivered from PIC. They have traditionally had a 3-4 week delivery for these types of gears, at best.

Andy B.

Re: Drill Motor Gear Specs?
 

Baker,

They must not like you too much. I get my 0.7 module gears from them in 2 weeks. It must be the accent.

Does this violate your "Don't bother posting" rule?

-Paul

Re: Removing Drill Motor Gear
 

At a recent team meeting, Ryan informed us that he now plans to use a Dremel to remove the pinion from the drill motor. Does anyone have any suggestions or advice for this? I'm a little worried that this might end up damaging the motor, can anyone confirm/deny?

Re: Drill Motor Gear Specs?
 

No, No, No; do NOT use a dremel. Use a press and push the gear off. Please see my post above in this thread. You could cause damage to the motor if you cut it off with a dremel.

-Paul

Re: Drill Motor Gear Specs?
 

Well the experiment has taken place, and with much success. While I agree that a press is a much safer bet, I had a very hard time fitting a plate between the pinion and the motor, so to the dremel I went. I first masking taped the ENTIRE motor, so that shavings would be reduced to a minimum. Instead of using a cutting wheel though, I used a grinding stone to grind away 2 semi-flat places of the gear without going all the way to the shaft. After this, I put the motor is a vice and tightened untill..crack went the pinion down one side. After this it popped right off with a piece of brass as a punch and a ball peen. I cannot be happier with the outcome and had no bad experience using the dremel to do this. Some teams that have a hard time trying to press the pinion off should look into this as a fast and easy alternative, in my opinion.

-Rc

Re: Drill Motor Gear Specs?
 

Are you sure it was a success? Did you try to run the motor yet? Better make sure you didn't bend that output shaft when you...dremeled... it off. Also, when you agree with Paul saying the correct method of using a press is much safer, don't turn around and recommend other teams go to and attempt what you did. Even if your motor did not get damaged in the process, other teams might not get the same outcome.
Out of curiosity, what and how do you plan to attach another gear to the Bosch with its very small metric output shaft?

Re: Drill Motor Gear Specs?
 

Never underestimate the strength of those small motors. If you really wanted to, you could do anything with the pinions. For example, my team had many left over fischer price motors, so one day I took one home and swapped out pinions. I first used a diamond dremel cutoff wheel to cut a slot into the gear, almost to the shaft. Then, I ground off the teeth of the gear (of course with the motor covered so shavings dont get in it). Then I put the gear into a vice, put a hardened steel pin to the shaft and yes, smacked it with a hammer until the motor popped free. The motor and shaft were in perfect-looking condition, so I commenced in "pressing" the new gear on. This was a little more tricky to do... First I determined the diameter of the hole in the new gear, drilled it, and prepped for "pressing". This was the hard part; I first put the motor in a vice. Then, I took a .5" peice of aluminum, and drilled into it a hole with the diameter of the outer diameter of the gear. This way, you put the gear in the plate, put the gear onto to motor, and smack away with a hammer, yet again. The end result was pretty good, but I wouldn't ever use it on a robot. Don't be ghetto. Do it the real way. To test this gear, I rigged it up so that the shaft was clamped down, and I got some huge vice-grip clamps around the gear and twisted as hard as I could. That was like a 15 inch lever, and it took a lot of force, I'm guessing 50 foot pounds to make the thing twist a little. So... the moral of the story is that you can do this for small projects, but not robotics. If I made a drive train that used this method of pinion removal, every match we played, I would be praying. Yea... as Andy Baker and Paul Copioli do, just use an arbor press. Makes life a lot more secure. As well as your drive train.

Re: Drill Motor Gear Specs?
 

I was just looking at

http://www2.usfirst.org/2004comp/Spe...inion_Gear.pdf

It shows 13 teeth NOT 15 like everyone is reporting?

What's the verdict? Is it 13 or 15?

ARGH!!!

Re: Drill Motor Gear Specs?
 

No doubt about it. The gear IS 15 teeth. The drawing has been wrong since last year. If you are unsure, then count the number of teeth on the motor that came with your kit. I have our motor in my hand and it is definitely 15 teeth (same as last year).

-Paul

Re: Drill Motor Gear Specs?
 

Whew...what a relief!
I was just working out our gear ratio's - 2 less teeth makes a BIG difference.

Thanks for confirming Paul.

Important - Oversize Teeth
 

Please look at this thread if you are designing your own gearbox for the drill motor:

http://www.chiefdelphi.com/forums/sh...ad.php?t=24181


The bottom line is that I have designed my gearbox with a 0.006" increase in the center distance due to the oversized pinion, but please read the thread for details.

I am using a 56 tooth gear to mate with the 15 tooth gear. My standard center distance would be 24.85mm and I am using 25.00mm (0.015mm ~ 0.006").

Also,

If you plan on using the gear from the drill motor then you need to get your mating gear at www.pic-design.com. Beware that these gears take at least 2 weeks for delivery. I ordered mine on 1/15 and still have not received them.

I hope this helps.

-Paul

Re: Important - Oversize Teeth
 

... maybe its the accent ... ?? :D :D

sorry ... I just couldn't help myself ... :p