On 2/10/2012 19:36 PM, Martin Riddle wrote:
wrote in message
...
Grind a tool from a hacksaw blade, mount it in the tool post, and use
the
carriage
[Rick]

So, just a sharp knife point thing?

Thanks,
Dave


I was going to mention cleaning between the communicators. Use a round
cutter, to scoop all the surface crap out.
Some also bevel the edges of the communicators so they don't tear up the
brushes. For small motors a ball point pen is usually used ( that should
give you an idea)


Some folks advise against beveling the edge of the bars. It doesn't
really help the brush slid onto the bar. But it does widen the gap and
reduce the surface area for brush-bar contact. This can increase brush
sparking/burning.

On large machines, GE and WE always advise cleaning the slots but
keeping perfectly straight bar edges.

Using a knife wouldn't be my first choice, it's too easy to actually
carve off some of the copper. Someone mentioned a custom ground blade
to fit the slot, and that's best. Just wide enough to get all the mica
and not leave a thin sliver on either side, but not so wide that it cuts
away any copper from the bars. That's what we did in the Navy's motor
rewind shop (lot's of DC motors of various sizes on submarines :-)


daestrom