need to learn to cut a comm.

[rock hard]

will a basic mini lathe like the 7"x12" work on motor comms?
or do I need smaller?
I want to do my 500 and 380 and micro motors.

any special tool needed to hold the comm in the chuck?

[Manning]

A specialized comm lathe is the ultimate solution, as it holds the arm exactly like it is in the motor.

I've tried cutting comms with a regular lathe about 20 years ago. First tried putting it in a 3 jaw chuck gripping the stacks. Didn't work worth a flip. The stacks aren't perfectly concentric with the comm, so the cut actually made it worse. Tinkered around with some other techniques, but nothing turned out like a cut on a real comm lathe.

If you have a good collet, and a way to hold the other end of the shaft, it might work, but I'm not sure.

[Joat]

most 7x's as they are commonly referred to are ok for non precise work out of the box, but runout will be pretty bad, I have a grizzly 7x 12 that has some important mods to it,
tapered headstock bearings - is a must
adjustable backing plate for 3 jaw chuck- I can get runout under .0005 with a 3 jaw chuck ,dont need to use a 4 jaw to get these kind of low runout numbers

["N8"]

Not to say that I dont believe you... meehidont believe you can get runout to half a thousandth. Heh how do you accomplish this? A standard 3 jaw is hard to get a part within 5 thousanths on a microlathe.

[Joat]

Originally Posted by "N8"

Not to say that I dont believe you... meehidont believe you can get runout to half a thousandth. Heh how do you accomplish this? A standard 3 jaw is hard to get a part within 5 thousanths on a microlathe.

Because the backing plate is adjustable, so I can adjust the runout using the backing plate

http://warhammer.mcc.virginia.edu/ty...tTruBackplate/

I had this guy build me one, one of the best upgrades and a must if you want to use a 3 jaw and get decent results

[rock hard]

so a 4 jaw is better if your looking to get a lathe?

how about the combo lathe/mills? to cluttered?
I was thinking it would probably be better to have a seperate mill since I have the room.

[Joat]

Originally Posted by rock hard

so a 4 jaw is better if your looking to get a lathe?

how about the combo lathe/mills? to cluttered?
I was thinking it would probably be better to have a seperate mill since I have the room.

Sorry did not see your post, if you have a nono adjustable backing plate then yes a 4 jaw,if you have a adjustable backing plate then 3 jaw, I have a 4 jaw and it's still in the box, also a 4 jaw is good for non round shaped items.