Question for Grizzbob and other electric know-it-alls/gods

[tadium54]

Ok, now that the title caught your attention, I'm about to cut the comms on some motors to re-sell. what is original size for the comms(brand new) and what is the smallest comm size you would safely run before tossing it?

[highroller]

Comm size from the factory varies between .290 to .285 depending on what each motor builder feels is the ideal comm diameter for making the most power. When diameter is .270 that is the size when lamenations are too thin to cut or use. Generally when it gets near .273 I think about replaceing the armature or buying a new motor. I use digital calipers measuring the comm before and after cutting to know when I'm getting near the end of lamenations.

[tadium54]

Ok thanks highroller(my appologies for not putting your name in the title- I know youre as knowlegeable as grizzbob) any one else have input?

[Grizzbob]

Wow, kinda cool to see someone asking for me publicly... :p Anyway, I agree, most of the regular diameter comms I've seen start at about .290"(& the large-diameter ones like what Reedy uses on some of their 19 turn & other motors seem to start at around .335" or so), & in general when a regular one gets down under .270 I'll stop cutting on it anymore & start auditioning a replacement motor(though I'm not sure how far down you can go with large-comm motors, haven't used them long enough yet.. ;) ). And for when it'll make its best power, it seems to me that many of mine seem to be their best between .280 & .270(so timing can mean everything when setting up some motors for a big event).....Oh, & sorry it took this long to respond, but that's just the hours I work now, just got home less than an hour ago.... :cool:

[tadium54]

Its only for stock,and they're all trinitys, so thats good to know. is it harmful to clean the motors with high pressure water? University strips what little money I have for RC, and motor spray isn't really an option right now

[highroller]

Depends on how high the pressure is coming out.
For a cheap alternative and people who have allergic reactions to certain chemicals soap and warm water is a good alternative. Disassemble the motor, use a soft toothbrush or wrap to clean for armature use a rag and gently wipe the surface. Air dry, wipe dry or use Rubbing Alcohol to aid in drying (water won't hurt it). As an alternative to RC Brands of motor cleaner I use the automotive brands of Electric Motor/Contact cleaners which are cheaper and not as harsh as brake cleaners.