by
Daniel J. Dyke
We have all broken in gears by a variety of methods and all of them seem to involve running the motor for an extended period of time. What I was wondering was whether or not this process could be shortened by using a small file and filing them smooth first. The answer is obviously yes. This type of experiment usually ends with me destroying at least one example of the subject in question. Let me assure you no gears were harmed or injured in the writing of this article, but a cat was when I tripped over him while filing and walking at the same time. I attribute it to chewing gum while doing the above.
The car in question was my SCX Peugeot rally car which has been the object of a fanatical quest of mine. If you have ever turned an SCX wheel by hand, you know with an almost religious certainty that the maker of these cars had not a clue about what gear mesh was. The problem is exacerbated on this vehicle because it is four wheel drive. Even after breaking the drive train in with the toothpaste treatment, the thing still sounded like my wife's garbage disposal.
I. Fixing the Pinion
B) A Step by Step
Step #1: Remove the body and pop the motor out of the chassis. Usually the motor comes out, as in the case of the SCX, by pushing up from the bottom of the chassis on the front of the motor.C) Test the mesh to see if it got better. Don't expect SlotIt style mesh without a lot of work. Redo the above process or go to the next step.Step#2: Hold the motor so that the armature stops turning, then run the tip of the round file between the first pair of teeth and find the rough spots. On my gears this was the whole surface.
Step#3: Gently run whichever file best fits the nook and cranny you are working and file between the teeth until it moves easily. Stop, you have achieved Nirvana. You are not trying to reshape the gear but to make the surface smoother.
Step#4: Go to the next set of teeth and repeat the process until all teeth have been filed.
Step#5: Clean the gear, replace the motor in the chassis and lube the gear with a gear lubricant. Gear grease is different than the engine oil. Ray carries this, but if you don't want to make the drive you can use engine/camshaft break in grease or white lithium grease from the automotive store.
II. Fixing the Crown Gear
This is a little more difficult. A bad crown gear is a tough cookie, but it often is the real culprit. I once had a bad SlotIt crown gear and that is rare. You can file each tooth as above, but something I have noticed is that sometimes the valley between two of the teeth is not as deep as the others. This has to be opened by either had to filing with a triangle file or cutting it carefully with a razor or knife.
III. Running the Gears In
When this is done you should still run your gears in. A suggestion here would be to get an old motor, if you have it, and put the gears on it and let it run a real long time. That way you don't wear your racing motor out. Then put the gears back on your racing motor. If you do be sure you align them exactly like they were run on the motor used to break then in.
CONCLUSION
Hopefully you will improve your gear mesh and won't destroy your gear set. Work slowly and don't get impatient.
CAVEAT EMPTOR: Well you aren't paying
for this help. You have to remember that I am an amateur and as such write
these articles from my own experiences. I try to communicate these
experiences as accurately as possible, but still will NOT assume responsibility
for your or my mistakes. If you want a guarantee then what I guarantee
is that the things mentioned in this article will not work. If something
does work and you don't want it to, then I will gladly break it for you.
A five pound sledge in the middle of a SCX rally car, priceless!