James
06-07-2005, 11:33 AM
I picked up a Cobra Pro 2k comm lathe (thanks Rob), and would like to work on my cutting technique, so some tips would be nice. I know a few guys on this site cut their own comms (bb, etc)..
what i know so far:
Bit sit's upside down, cut's from the end of the comm toward the tabs.
Comm spins away from you (opposite to conventional workshop lathe)
use 4 to 6v for 27turn type motor, and 12v for 55turn lathe motor?
mark comm with a black marker before cutting
what I'd like to know:
Should you only ever cut from right to left? (depends on your lathe i spose) or can you start in the centre of the comm? I tried starting in the centre, but it messed things up when I went from centre to right. (bad idea)
Do you use cutting fluid? is it required?
Carbide or diamond? I've read carbide is better as diamond blades chip easily, carbide are also cheaper.
Speed of the cut? how fast? maybe 15 sec from right to left?
What kind of shims to shim the motor up on the plates? Should I buy a set of teflon shims?
Any other hints/tips appreciated. I've found a lot of tips on some forum's that "Big Jim" posted in, including orientation of 'bits', direction of rotation, etc...
Speaking of Big Jim, not sure if you guy's knew, but he passed away two weeks ago :(
He was an r/c motor GURU (and hero)...
If you want to learn more about r/c elec motor maintenance or even building, buy his book, Big Jim's "black book"... from any hobby shop.
James
what i know so far:
Bit sit's upside down, cut's from the end of the comm toward the tabs.
Comm spins away from you (opposite to conventional workshop lathe)
use 4 to 6v for 27turn type motor, and 12v for 55turn lathe motor?
mark comm with a black marker before cutting
what I'd like to know:
Should you only ever cut from right to left? (depends on your lathe i spose) or can you start in the centre of the comm? I tried starting in the centre, but it messed things up when I went from centre to right. (bad idea)
Do you use cutting fluid? is it required?
Carbide or diamond? I've read carbide is better as diamond blades chip easily, carbide are also cheaper.
Speed of the cut? how fast? maybe 15 sec from right to left?
What kind of shims to shim the motor up on the plates? Should I buy a set of teflon shims?
Any other hints/tips appreciated. I've found a lot of tips on some forum's that "Big Jim" posted in, including orientation of 'bits', direction of rotation, etc...
Speaking of Big Jim, not sure if you guy's knew, but he passed away two weeks ago :(
He was an r/c motor GURU (and hero)...
If you want to learn more about r/c elec motor maintenance or even building, buy his book, Big Jim's "black book"... from any hobby shop.
James