pic: Another stripped VexPro gear

[Thayer McCollum]

We had a VEX gearbox failure in the same type of gearbox. But it was the gears that failed, it was the casing. We took an especially rough underside impact and sheared the CIM right out of the black plastic. So... you know... we drove almost a whole match with a CIM hanging solely on its wires. (No way were we going to hit that E-Stop)

[lethc]

The same thing happened to us at the OKC regional. We believe that a bind was caused due to a broken PTO chain and resulted in a stripped gear. We are using these gears on our Vexpro ballshifter gearboxes.

[frcguy]

As promised: http://www.chiefdelphi.com/media/photos/43781

[LSanchez439]

Originally Posted by techhelpbb

Hey FRCGuy are you sure you don't want my 2 lightly used 24 tooth Vex gears?
Cause...

It's probably too late for me to broach you steel gears.
I also don't have 24 tooth steel gears to start with and I doubt I can get them fast enough.
Going to put these on my list of 'coming soon'...

When you say 'broach' them some steel gears, what exactly are you referring to?

[FrankJ]

Originally Posted by LSanchez439

When you say 'broach' them some steel gears, what exactly are you referring to?

You can Google "broach" to find some examples, but in this case, it is pushing a hex shaped cutting tool through a round hole to make a hex shaped hole.

[techhelpbb]

Originally Posted by LSanchez439

When you say 'broach' them some steel gears, what exactly are you referring to?

Buy a gear with a 1/2" round hole (also maybe a keyway) and push broach it 1/2" hexagonal.

The push broach looks like this (this one is from Dumont):
http://www.andymark.com/product-p/am-2204.htm

It fits in either a hydraulic or arbor press.

The 20 tooth steel gear I did for other teams look like this before I broach them:
http://www.andymark.com/Gear-p/am-0186.htm

You know that intelligence test where you put the round peg, in the round hole and the square peg, in the square hole?
In this case you push with about 1,100lbs of force until the round hole chisels out to a hexagon
Proving once and for all - brute force can solve problems.

[MVCI]

Is the output direct driving a wheel (ie output shaft going through a rigid frame)? Look into the possibility for relative motion between the output gear and its driving gear. This could be caused by loose transmission mounting or flexing of the plastic case. With extra load/impacts on the gears being part of this game and improper gear mesh (caused by relative motion between gears) I imagine this could easily happen.

[Reptilefox]

That exact thing happened to us (3230) at the Idaho Regional!