[Schurkey]

Originally Posted by lust4speed

Which raises a question. If the commutator is cleaned up in a lathe, is it necessary to trim down the mica? I couldn't tell whether you were referring to using a lathe as usually not needed, or trimming the mica usually not needed.

Ideally, both processes would be performed. Realistically, neither usually are needed. If a shop has the armature lathe, they probably also have the mica-saw. I have neither. I carefully inspect the armature bars for "smearing" (some copper from each bar may get "pushed" onto the mica next to the bar.) I remove any smeared copper with a fine pick. A foot of emery cloth to polish the copper, final cleaning...and I'm done.