In Need of Gears and 775pros

[aldaeron]

Originally Posted by michchinn

Will using a steel 20t gear in the 3rd stage accelerate wear on the aluminum 64t gear that it meshes with in the third stage?

Perhaps. There is a lot of discussion about 3rd stage gearing wear for a Ball Shifters on this thread. I would contact some of the folks on there that have put these gearboxes through very, very tough trials.

-matto-

[Doug G]

Originally Posted by aldaeron

Perhaps. There is a lot of discussion about 3rd stage gearing wear for a Ball Shifters on this thread. I would contact some of the folks on there that have put these gearboxes through very, very tough trials.

-matto-

We went to 3 regionals this year and wore through 5 20T VexPro gears with our 3rd stage of Ballshifters. We ended up switching to the Andymark steel gears (broached hex). At the end of our Idaho regional, our 64T VexPro gears were trashed, luckily we had replacements for those.

Some of our issues were due to the lack of securing the 3rd stage to the BallShifter. We were having a lot of binding when we tightened the 3rd stage too much, so we tried to find a happy medium between too loose and too tight, we think this caused some issues with gear tooth engagement when it experience shock loading.

This year was rough on drive trains.

[techhelpbb]

For those of you that broached gears how did you align things?

I tried a rotary broach in a Bridgeport but found it difficult to get a good center. The existing keyway in the gear would end badly on a coaxial indicator. I tried a few times with a 0.2 edge finder and the DRO but still managed to be broached straight but slightly off center.

It is either I am off center or my back plate protecting my chuck face is not rigid enough. It is strange because I drill out the hole to 33/64" and chamfer before I go in. Center does not move. I have not tried this much lately....maybe just have not gotten the knack of it.

[asid61]

Originally Posted by techhelpbb

For those of you that broached gears how did you align things?

I tried a rotary broach in a Bridgeport but found it difficult to get a good center. The existing keyway in the gear would end badly on a coaxial indicator. I tried a few times with a 0.2 edge finder and the DRO but still managed to be broached straight but slightly off center.

It is either I am off center or my back plate protecting my chuck face is not rigid enough. It is strange because I drill out the hole to 33/64" and chamfer before I go in. Center does not move. I have not tried this much lately....maybe just have not gotten the knack of it.

We use a standard push broach, and it works fine for keyed gears. Fine enough for FRC, anyway.

[techhelpbb]

Originally Posted by asid61

We use a standard push broach, and it works fine for keyed gears. Fine enough for FRC, anyway.

That is my Plan B. Kind of hoped to sort out where the weak points of Plan A were and if there where a good fix.

Originally Posted by R.C.

If you have a rotary broach, I would use the lathe instead of the mill.

Seems a similar alignment issue. Gear is just a bit too big for a 5C collet. Plus the collet would not likely provide the support for the thrust involved. It is an even number of teeth so a 3 jaw chuck will not engage the teeth all the way around. My 4 jaw Chuck are all independent so then I need to center. The way I center I guess I would need to turn down a rod snug to the bore and use a dial test indicator.

Any other ideas cause my press is looking good right now

[R.C.]

Originally Posted by techhelpbb

For those of you that broached gears how did you align things?

I tried a rotary broach in a Bridgeport but found it difficult to get a good center. The existing keyway in the gear would end badly on a coaxial indicator. I tried a few times with a 0.2 edge finder and the DRO but still managed to be broached straight but slightly off center.

It is either I am off center or my back plate protecting my chuck face is not rigid enough. It is strange because I drill out the hole to 33/64" and chamfer before I go in. Center does not move. I have not tried this much lately....maybe just have not gotten the knack of it.

If you have a rotary broach, I would use the lathe instead of the mill.