shimming

[NinjaAxle]

I seem to have an evil gearbox, I tried shimming it and it came out Ok-ish for my first try shimming a gearbox (sounded pretty rough). I then had a wiring issue and sent it in to a shop get rewired and re-shimmed, and it came out if anything; worse. Is there anyone any good at shimming that would be able to find out what's up and sort it out for me? It's a G&G cqw rush with the blowback de-activated, new motor, and short stoked gears (to reduce the fps).
Thanks
Alex

[Scotty Dog]

Re: shimming

Does it still have the stock G&G copper bushings in it? They've certainly worth swapping out.

Are you still running a stock motor? Have you checked motor height, its usually the first culprit for an abnormally loud gearbox.

[sparrowhawk]

Re: shimming

you changed the motor,so it may have a different pinion gear which doesnt mesh well with your bevel gear,also did you change the pistol grip

[Figjam]

Re: shimming

Other causes for horrible noise can be mismatched brand gears, particularly the pinion to the bevel, have you changed any of the gears or motor? I put a TM eg3000 with SHS gears in an old build of mine and I could never get the noise down to a level I was happy with. Swapped the pinion to SHS and things got much better.

[NinjaAxle]

Re: shimming

I changed out the bushing, and put a lonex motor in it. the pinion gear wasn't meshing well so I switched back to the stock g&g one, the gears are all g&g stock ones (i put some lonex ones in but they seemed to be too small of a diameter 0.05 mm out) so it has all matching g&g gears. as for motor height, I have put the motor all the way in, and out and it sounds horrible everywhere.

- - - Updated - - -

i did change the pisto grip too, i have a g&p spr grip on it

[sparrowhawk]

Re: shimming

changing the pistol grip can make the motor sit at an incorrect angle causing all kinds of problems, you've changed a lot of things there...... so a lot of issues can occur, its a matter of elimination you really need to go back to stock parts and add one change at a time, till you find the culprit tbh it could be any number of things or severall added together,you might even have a noisy motor or bushing not seated right.....have you noticed extra heat from the pistol grip,motor, wires or battery

[NinjaAxle]

Re: shimming

no, i haven't noticed any heating up

[richw]

Re: shimming

I'd try the original pistol grip and watch for wire routing, the wires can move the motor and cause it not to sit right.

[NinjaAxle]

Re: shimming

i have tried a combination of two motors, two pinion gears and 3 grips, and with all of them the gun still sounds horrible. it's looking like it's gonna have to be a full blown re shim

[whiteman]

Re: shimming

1. firstly when you instal a especially new gears, use a toot brush and some white spirit/acetone or any other solvent who is beloved by junkies, to remove a traces of old grease, sand and remains of metal chips.

2 sometimes gears / GB are not flat smooth and are unsymmetrical. try to flat it file down till you get smooth surface. Clean it up with solvent (tootbruch or cloth ).If you need use a metal polishing fluid / paste

3 .when you instal a new gears start from the mid.
a).put the smallest shiming at bottom of gear and spin the wheel.try to hear some noise. if no-->high of gear is correct. if yes- add one extra till you get noiseless effect
b) .insert a new shining at top of shaft of mid. gear. now, put other part of GB,bolt it (at lest 3-4 screws the nearest of the gear ) , and spin it. try to find any gaps between flange of shaft and bearings/bushing. add always the smallest no you have till you get smooth moment without any wobbling or grinding noise. then you can replace a shimming with a few of large size. ( 5x 0.1 = 1x0.5 )

c) Try to write done on paper which gear and how many shimming you added. it can be very useful when you lost a shimming accidentally. Also you will know a gap between flanges of gears

4. Other gear shall be instal in the same way.
5. Instal a motor and try to adjust the high of it. Do not instal a spring yet, coz you will simply shave off a gears.
6. If done correctly, add lubricant (oil, grease , lard, whatever you use ) ,then instal a spring, and try to finish motor adjustment under a spring load.

It is method of trial and errors. the worst of all when you fixing AEG.It takes a lot of time, but is very crucial and result always improves performance of our RIF (greater rof, greater trig reaction,lower noise or noiseless )

Sometimes you must a file down a cut off lever or ant other part of gearbox to have a right interval among a gear.
Technically the gap between gears shall be as small as possible ( i refer to stress theory ) However, the greater gap among them the lower noise. You need to fine a compromise

End of proces.

[SC0LLAY]

Re: shimming

thats is a far outdated method of shimming, look up bevel to pinion shimming on youtube or make an airsoft mechanics forum account you'll find several good guides there.