PDA

View Full Version : Home 'built' comm lathe


JeremyC
2009.12.07, 01:54 PM
I was having problems with my Atomic Standard BB (thread here (http://mini-zracer.com/forums/showthread.php?t=33249)), and concluded that I had to lathe the comm. Of course I don't have a comm lathe, so I decided to do the next best thing; use a wooden spoon and wire ties.

http://mini-zracer.com/forums/attachment.php?attachmentid=28631&stc=1&d=1260211860
The motor on the left was driven by two AAA's and the right is the motor that needed lathing.

This worked surprisingly well, but I wouldn't recommend doing it with pinions that you care about. The vibration causes the gear mesh to vary and the teeth did start to squeal a couple times.. I used a broken bit of a dremel disk to refinish the comm.

mk2kompressor
2009.12.07, 03:04 PM
any pics of the comm?

JeremyC
2009.12.07, 03:13 PM
any pics of the comm?

Here you go. I didn't think to take pictures of the before, but it was a darker copper; similar to left of where it was cut. I also cut a little too far to the right. This method was not very precise, if you hadn't guessed. Although it did work.

http://mini-zracer.com/forums/attachment.php?attachmentid=28633&stc=1&d=1260216742

Tjay
2009.12.07, 05:23 PM
You can also use a dremel with variable speed and set it to lowest rpm and then polish the comm. Yeah, polishing only not cutting... I use my $20 cordless dremel.

JeremyC
2009.12.07, 05:50 PM
You can also use a dremel with variable speed and set it to lowest rpm and then polish the comm. Yeah, polishing only not cutting... I use my $20 cordless dremel.

I have a variable speed dremel and am going to try polishing it :)

wildthing
2009.12.08, 06:07 AM
what will you use to polish the comm?

bermbuster
2009.12.08, 06:26 AM
the condition of the comm surface will tell you how much you must remove.
if the surface has shallow marks than you only need a light polish.
You can use a very fine pc of emory paper or some rouge(1000 or more grit). The easiest polishing compound to use is toothpaste. (small amount on a pc of cloth)
Just remember the idea is to get the comm smooth again. You will be removing like .001". More or less.....

JeremyC
2009.12.08, 10:59 AM
Thanks for the ideas berm.. The only polish I have right now is chrome metal polish; which is a very unabrasive polish. I have 2000 grit sandpaper and I can steal one of those nail buffers from my GF :)

I'll try the polish first because I suppose.

JeremyC
2009.12.08, 12:34 PM
After a light polish using the chrome polish.

http://mini-zracer.com/forums/attachment.php?attachmentid=28637&stc=1&d=1260293606

http://mini-zracer.com/forums/attachment.php?attachmentid=28638&stc=1&d=1260293606

JeremyC
2009.12.09, 01:24 AM
Put new brushes on this motor and ran it tonight. It is fast. :)

oopster
2010.01.26, 04:46 PM
Ouch! Please don't do that to a motor!

Hudy do a range of comme lathes. Think the best option for mini-z is the slot-car version, as the standard scalextric motors, are the same shape and size as mini-z motors. They're not cheap, but Hudy are a quality name.

Here's the link to the slot-car version
http://www.hudy.net/xhudy/products/proddesc.php?prod_id=86&kategoria=61

I've got the "fully-auto" big version, but dunno if that would work for mini-z type motors.

B-main
2010.01.26, 10:30 PM
for polishing my comm i use MOTHERS MAG& ALUMINUM POLISH.its not to abrasive .and my wal mart dremel