RC10DS Eats Spur Gears

[bkunar5356]

within the past week, i have gone through 3 spur gears. at first i was using a traxxas 54 tooth 32 pitch gear, i had to drill 2 new holes for proper mounting. then since i couldnt find those anymore, i switched to a 60 tooth duratrax. my clutch bell is a 22 tooth. i was wondering if i was meshing the gears too tight or too loose, i dont think it was too loose but i dont thinnk too tight could be a problem. i was wondering if maybe i should make one out of aluminum or steel. my thought is that the aluminum is softer than the steel clutch bell so the gear would go first if something would happen. what should i do? i have access to equipment, it should be fairly easy to make an aluminum spur gear but if i can use something that is more readily available i would like to. any advice is appreciated

 

[Ajeauxdn]

I have a duratrax that eats them bad too. Right now I am getting some aluminium gears made. does your car have a 2 speed, if so this could be reason for them stripping, a bounce anytime its in 2nd would cause them to strip. Another thing that may cause it is if your slipper clutch is not working properly. I am no expert on these things but seems to me that 2 speeds often cause mroe trouble than there worth.

 

[bkunar5356]

well its not a 2 sp but the clutch may not be quite right, I'm no expert either, I've only had my car for a little more than a week. i did notice that you were having some gears made and i am thinking i will make some for myself. if you could, please tell me a little bit more about what you are making and how you are making them, also what they will be used on/with. i have assecc to mills, lathse, CNC mills and CNC lathes so i have just about everything that would be needed, i would probably go for the CNC mill and just do it all in one step. if i do make these, i will probably try to make about 2 or 4 of a few different sizes so i can swap them out and if i break one or lose one i have a few spares

 

[LarryA]

Generally stripped spur gears are from improper gear mesh between the clutch bell and spur. They should last pretty long in not almost forever.

 

[bkunar5356]

okay larry...or anybody else for that matter, how do you properly mesh a spur gear with the clutch bell?

 

[mcvickj]

A piece of paper between the spur gear and clutch bell will give you the proper mesh.

 

[wdavidhicks]

When you're done there should no binding at all between the clutch and spur when you spin them.

If I hold the clutch bell and move the spur it feels like only micro-millimeters of backlash. I had it adjusted to closer tolerances than that and found that my spur gear is not perfectly round. (or not perfectly centered on the slipper disk.) It would very lightly bind for several degrees of rotation and then free up through the remainder of the rotation with zero or near-zero backlash.

This takes a lot of tightening and loosening of the engine mount screws to get it right. Make sure the engine is straight and not cockeyed in the mounts. I use the engine mount slots as a reference.

Once that's done and your mesh is good, cinch down three of the mount screws, remove the fourth, cinch it back in with Blue Loctite. Remove, Loctite and cinch each of the remaining screws, one at a time.

If you're gonna grind your own gears the Traxxas gear pitch is 32 pitch SAE. 1/8 scale vehicles are normally 32 pitch metric.