today i was polishing the shafts on a used arm i had with 2000 grit sand paper and i decided i would test it out on the comm and it polished the comm up real nice just as good a my comm lathe would. have any of you guys ever tried that. if not just take a spare armature put it in your dremel at a low speed and give it a try it looks like you just skimmed your comm. i dont know how true it is but i didnt take off to much material. i might just do this in between heats and then each week just true it up before i race again. what do you guys think?
If your removing enough material so that the appearance is the same as your comm lathe then you must be removing at least as much material at the critical low points as you should if you have skimmed it correctly. So what is the advantage over skimming the motor?
Did you measure the new diameter of the comm with a micrometer to find how much you had taken off? What seems like virtually nothing to you may be in fact more than your lathe would remove. Remember the feed on your lathe is very fine.
The difference between skimming and sanding the comm is that when you sand you cant get the comm as round. You may in fact make the comm less round than it already is which will mean you will have tor remove even more material when you next skim the comm.
i was just thinking the sand paper wasnt taking off enough material to take away the trueness of the comm buy i guess any material is enough, and it does take off as much as my lathe would to get the shiny finish.