by waaytoomuchintothis » Mon Jul 13, 2015 9:14 am
Just in case it comes up, I think I should mention that when you solder the tubing to the motor shaft in order to use standard pinions, there are a few things that absolutely must be done to be successful the first time...
-Splined or not, the motor shaft must be cleaned and roughed up; I use a small diamond file to do this, with the motor running.
-For what Harry is talking about, which is what I use most of the time, careful attention must be paid to the end of the shaft to round AND smooth it to prevent friction against the crown. The friction of contact with the plastic or bronze crown is too small to be noticed if the motor shaft is properly prepared. Remember, one side of the shaft is helping, one side is against you- if you shim the wheels against the chassis in such a way as to allow contact only on the side that helps you, even that insignificant contact is on your side.
-All of the above is to be done before the pinion is placed, of course, which brings up the last point; soldering the tubing needs to be hot- 850 degrees or more to assure a good flow. Lots of flux. When you are satisfied with the bond, de-burr thoroughly so the pinion can't be distorted when pressed on.