what might cause this?
 

hi guys. i'm trying to understand what cause this to happen to the teeth of the piston body? i'm planning to change it to a deepfire if possible but i;m just wondering what cause this.

any input could help.

thanks guys.

http://i33.photobucket.com/albums/d5...e/P9060038.jpg

Wrong use of grease which caused the teeth to chip off?
Gears were not aligned properly with the piston?
Cheap piston?
What's the make of your gearbox, and what upgrades and battery are you running?

ah one of my pistons did that from a full auto burst with a lipo battery

waow, ALL the teeth are stripped.

somehow the piston got stuck, or it was going one way, and the gear the other.
what system is it?

it could be excessive speed or excessive torque, or mis-synchronisation at one point.

it's from an JG MP5 navy.
the first time i notice this only 3 teeth were stripped, then next this.
so i will need to make sure i align the gears and the piston next time.
i'm sure though that i did that.

Oh there's your problem.

You used a stripped piston.

Gear alignment doesn't cause that problem, neither does improper use of grease, or anything else stated above beside the fact you put it back into the gun when you realized it was stripped.
Buy a real piston (systema) and real gears (systema) and you won't have that problem anymore.

thanks for the reply guys...
i thought of this for a while and i think that the teeth gave up because of the spring.
the teeth laid in a manner towards the spring, so maybe it had a hard time with the spring.
thanks again guys...

my black systema piston failed exactly like that. I got it all new in a factory drag and drop m120 mechbox.

Don't reuse marginal parts. If they're worn...toss them.

Take a good look at your gears as well, especially the sector gear teeth that engage the piston. If they're worn, replace the entire gear set (or else the worn gears will just prematurely wear out the new piston).

If you've got the stock spring in there, consider dropping down to a Modify S100 or S110. The "weaker" springs will put less strain on your motor/gear-train and your internals will last a lot longer.

Or...keep it souped up and just resign yourself to replacing parts frequently.

Take care when swapping pistons/piston-heads...ensure that the combo that you end up with is long enough so that its teeth index properly with the sector gear (or else you'll just strip the new piston). For example, a deepfire piston and System silent head set that I had in one rifle was about 1-1.5mm too short. Once I used a washer to extend it, it worked just perfectly. The piston is all worn out now...but that's after about 8-9 bags of bbs (and at one point it was setup to shoot 1300+rpm).

Best of luck.

Tys

Just to note, the old systema black pistons are crap.