I used to break-in the bushings on stock motors but I don't anymore. I've found a technique that is easier, faster, works better and you don't have to worry about getting all that abrasive stuff out of your bushings. You polish the shaft. This works for a used motor as well as a new one.

Go to the hardware store or a Pep Boys and get some #1500 or #2000 grit wet-or-dry sandpaper. Pick up a sheet of #400 too. Also, some metal polish like Blue Magic or other low abrasive polish.

Take the motor apart. If it's a used motor you are rebuilding, it could have some score marks on the shaft if you forgot to use some good oil on the bushings. Check the armature in a drill and sand the score marks with the #400. If you don't have any marks, start out with the fine stuff. #2000 grit paper will polish the shaft almost like a mirror. Next, take a clean rag and put some polish on it. Turn on the drill and go to it. You really only need to do the area that rides in the bushing but do the whole thing. It looks pretty.

This should be done as your last step before assembling the motor. If you still have the comm to cut, do it before polishing or it will leave scratches that you just polished out. Put the necessary spacers on each end to center the armature in the magnetic field (see the Black Book for the proper way).

Now for the important part. Just before putting the arm in the can, put a drop of TRIBO R/C Power Matrix Commutator Lubricant on the shaft near the spacers. Put it in the can and use the same procedure for the endbell. Once you have the motor together and the endbell screws tight, take the flat part of a pair of pliers (or similar tool) and lightly tap each end of the shaft a few times. This centers the bushing on the shaft. Check your spacing. Change if necessary.

Spin the arm by hand. Feels good doesn't it?

I have heard off people using toothpaste i have tried it myself but the best luck i have had is polish it with mothers polish get it right at your local automotive store or wal mart.

Brandon

What about polishing the comm?

silly question ?

Where can I purchase the Black Book at ?

Check out Amazon.com. Look for "Big Jim's Black Book." I believe that's the title.

Another good polish is simichrome (spelling ?) and I found mine at a local motorcycle shop. leaves a motor shaft looking like chrome and feeling slick as ice

Try diamond compound. The green color.

would mothers work?

Polishing the arm is a bunch of CRAP that lots of people do because of the black book,I found with bushings usally after a run or two you have plenty of slop in your bushings.I raced brush Stock for years,My motors were the fastest at the track and I built thousands of them. Why would you add excessive clearance to a motor(wear it out before you race it)? So the armature bounces instead of the brushes? The best way to get true horsepower is with a motor with close tolerences and high silver serated brushes.You dont see Nascar build engines like your lawn mower do you. Also the other thing that makes a fast motor is a well ballanced armiture.

.....

scotth"s my hero

Ahhhhhhhhhhhh hush red.

Polishing your shaft, Hmmmmmm. Gee Scott this sounds like your kind of discussion! lolAhhhhhhhhhhhh hush red.

Polishing your shaft, Hmmmmmm. Gee Scott this sounds like your kind of discussion! lol

Got to admit, It's funny seeing "Polish your shaft" on top everytime I visit HobbyTalk.
Hi Cliffy:wave:

I know, Hank is gonna fuss @ me for bringing that to light. lolGot to admit, It's funny seeing "Polish your shaft" on top everytime I visit HobbyTalk.
Hi Cliffy:wave:

Yhe "black Book" does not say polish the arm, in fact it says the commshould have a finish similar to looking @ a CD. Polishing the shaft is essential to building a fast stocker, especially @ a hand out motor race. I agree with you about wearing the motor prematurely and I wouldn't go to all that trouble for club racing but @ a big race you need a shaft and comm that is about 1/2 worn out to be fast.Polishing the arm is a bunch of CRAP that lots of people do because of the black book,I found with bushings usally after a run or two you have plenty of slop in your bushings.I raced brush Stock for years,My motors were the fastest at the track and I built thousands of them. Why would you add excessive clearance to a motor(wear it out before you race it)? So the armature bounces instead of the brushes? The best way to get true horsepower is with a motor with close tolerences and high silver serated brushes.You dont see Nascar build engines like your lawn mower do you. Also the other thing that makes a fast motor is a well ballanced armiture.