Same gear stripped 3 times in under 100 rounds, PLEASE help!

[timberwolf61]

Alright, so my primary gun is a hexagon productions ppsh 41. After a while it stopped shooting and there was a few problems with it, including a stripped gear. Okay, I figure the parts it comes with are crap so I upgrade half my gearbox. I start shooting it again after its been fixed just to have that same gear stripped less than 100 rounds later. The gun had jammed
that time around so I thought the jam caused it to strip so I ordered a new one. I just got the gun back a few days ago and tested it out today....40 or so rounds later I hear that same screeching sound and the gun stops shooting.
Can someone please tell me wtf is going on?!?!
Are maybe the other parts too high quality for the gear and causing it to strip? Or is it just a bad piece I'm buying? I'll be happy to provide links of the parts I bought...once evike is back up. the site is currently down.
edit: PROBLEM FIXED. Bushings were out of whack.

[Styrak]

Bad shimming? Or warped gearbox or bad bushings.

[timberwolf61]

Just realized I never said which one it is. It's the spur gear.
Also I just had it shimmed with some really nice ones so that's not the problem.
The gearbox itself looks fine so I don't think it's a warped gearbox. I've kind of overlooked the bushings though...could those tiny little things really cause the whole gear to strip?
I'm hoping that's the problem because it shouldn't be too expensive for new bushings and a gear.

[HKGhost]

the quality of the shims wouldn't matter if the shim job is bad. Are you doing the shim job yourself or someone else did it for you? Shim jobs takes a long time to do if you want a good job. After each gear is shim, everything needs to be closed up and test before moving onto the next gear. Your problem sounds like a bad shim job + maybe bad bushings.

[Acid_Snake]

The bushings hold the gear in place and keep it straight while the shims keep them properly aligned. So you see if any one of these is off or worn the gear can wobble while it spins and come into contact with stuff it shouldn't and it will wear and eventually strip. What bushings are you using? And you used "good" shims? That means little, Styrak was asking you if you shimmed the box properly.

I am not familiar with the hexagon gearboxes but if you have plastic bushings you should switch to metal ones ASAP.

[timberwolf61]

I had someone else do it for me, I'll have to ask him about it. I have the bushings that came with the gearbox.

[Acid_Snake]

Are they plastic or metal?

[HKGhost]

oh and I forgot to mention, if the same gear is getting f'ed up, if could be that the hole for the bushing or the bushing is out of alignment. I would check this area out first then the bushing itself.

[timberwolf61]

Yeah the bushing for that one wasn't lined up right, thanks. It works better than ever now

[ripanu1]

Bushings are to your gears like the foundation is for your house. It is very important to have them tip top and robust. If you have ever been in a vehicle where the wheel bearing is bad you will notice the howling, grinding and shaking that it does. Your wheel is not running true with the rest of the vehicle. If you can tip the gear back and forth "ANY" amount ,the bushing is toast. I use vernier calipers for the shafts and feeler rods from Mc Masters for the bearing I.D.'s . The better the fit ,the better your gear and shim job will turn out. Sorry for the rant lol. Cheers

[Ratters]

I like to remove everything from the gearbox shell during shimming.
The first gear (spur) generally uses a very thin shim to keep it from bottoming out against the shell

Then you can build the shims on top, put the gearbox together, hold it firmly together or screw it snug and do a push test on both shafts through the bearings

It's OK to have a fraction of movement

[Don't forget to clean out the old grease and feel for metal, if there's metal inspect your gears closely and your piston rack, cut off lever, anti-reversal latch]

Repeat with the second gear, (sector)making sure it just clears in mm the bottom gear, again, build it up, screw together, check for lateral slop, shim accordingly

gears slightly different, depending on the motor gear and drive gear, motor gear and drive gear teeth or mesh heights can vary

I like to put this gear up against the motor gear to see what type of mesh depth I get

This last gear (Bevel) can sometimes benefit from a few more shims under it, opposed to above it to help motor gear engagement be more integrated

Once these are all in and you've screwed the shell together use a thin dowel or screwdriver to check for free spinning. Slight resistance is ok, spinning with very little resistance is ideal providing lateral shaft movements are in the thousands

Now open it and put your piston in, close it up and make sure it's moving freely, not binding between the shell halves

If it's good do the same with the tappet plate

If all of this goes well you've got a smooth moving gearbox, reassemble, be aware your motor height is now different so test and adjust accordingly

You can also do an AOE mod at this point, or not

You should now have a gearbox that will give you reliability for a long long time

While the motors out its also wise to check for wear on your motor brushes and commutation

Hope this helps

[Ratters]

I like to remove everything from the gearbox shell during shimming.
The first gear (spur) generally uses a very thin shim to keep it from bottoming out against the shell

Then you can build the shims on top, put the gearbox together, hold it firmly together or screw it snug and do a push test on both shafts through the bearings

It's OK to have a fraction of movement

[Don't forget to clean out the old grease and feel for metal, if there's metal inspect your gears closely and your piston rack, cut off lever, anti-reversal latch]

Repeat with the second gear, (sector)making sure it just clears in mm the bottom gear, again, build it up, screw together, check for lateral slop, shim accordingly

gears slightly different, depending on the motor gear and drive gear, motor gear and drive gear teeth or mesh heights can vary

I like to put this gear up against the motor gear to see what type of mesh depth I get

This last gear (Bevel) can sometimes benefit from a few more shims under it, opposed to above it to help motor gear engagement be more integrated

Once these are all in and you've screwed the shell together use a thin dowel or screwdriver to check for free spinning. Slight resistance is ok, spinning with very little resistance is ideal providing lateral shaft movements are in the thousands

Now open it and put your piston in, close it up and make sure it's moving freely, not binding between the shell halves

If it's good do the same with the tappet plate

If all of this goes well you've got a smooth moving gearbox, reassemble, be aware your motor height is now different so test and adjust accordingly

You can also do an AOE mod at this point, or not

You should now have a gearbox that will give you reliability for a long long time

While the motors out its also wise to check for wear on your motor brushes and commutation

Hope this helps

[Ratters]

One thing, very important is the tappet plate. It must lay on a horizontal, neutrally flat plane across the gear, in a neutral fashion. If the gear is shimmed too high it will push the tappet against the opposite side of the shell and can bind. The tappet once the shell is together ( prior to full re-assembling) must be free to slide forward/aft as the piston does