shimming

[boogiebot]

i know that there is a wealth of info on here and some pretty knowledgeable people who know a ton about this sport as well how to tech their guns.

so i wanted to know how many of you shim gears when you get your gun. is this something that you do right away or do you play with the gun until it needs to be serviced before you worry about this kind of stuff?

[chaosrealm93]

i guess it depends on the person and the purpose of the gun. if the gun is bought mainly for the shell and the innards will be thrown out anyways, it would be worth shimming the moment you get it. on the other hand, if the gun is for mild use, i could see someone waiting until something needs replacing to do a shim job (sorta like a checkup for a car)

[RaisinBran]

I shim all my guns, it makes them sounds smoother and last longer, I ran out of shims to use on my WE so it's not as smooth as my others but you should definitely shim them!

[Hectic]

good advice if you are apt in takin a gearbox apart, and in most cases it womt significantly increase the life of the gun, of the shim job from the factory was that bad you would hear it.
my first gun was a jg m4 way back in 07 they argueably had the worst qc in the world at that time. It went 50000 rounds or more befor the gearbox cracked due to cold and dry firing.
id say if u can get it shimmed by a pro for free or cheap then do it otherwise dont fix what aint broke.

[ThunderCactus]

Depends on the gun.
Marui's get perfectly shimmed from factory
95% of other AEGs don't

And it's pretty well MANDATORY to shim a G&P before you even test fire it. They're got extremely weak axles and may only last a game without proper shimming, but may last 1-3yrs after getting shimmed.

[Hectic]

ahh well i know not to buy a g&p lol.
even my cyma seems to be holdin out with the stock shim job, hell my kraken has 20-30000 rounds on the stock build, guess ive been lucky.
dont get me wrong i see the need for a good shim job especially on high speed builds, just for me or another person who doesnt really have gearbox bilding skills its better to leave well enough alone till there is a need to rebuold then i can try a few times an if i fail just take it to a doc and get it done right

[ThunderCactus]

Just because a gun comes with a bad set of stock gears, doesn't mean you should pass up one of the most solid AEG bases ever made. Not to mention the best M249 on the market. They're upgrade platforms, you're replacing all the internals anyway so what does it matter if it has a hit-or-miss piston and weak gear axles? lol

Honestly if you're not pushing your gears very hard, they can run loose for a long time. It's more critical in helical gears since the nature of their meshing causes axial force.
But if shimming gears didn't improve performance, we wouldn't try so hard to get it perfect in industrial applications.

[Blackthorne]

Its your typical upgrade reality. If you are upgrading, and spending money on new parts, why risk destroying them because of wear and tear caused by misalignment? There really aren't many half measures in airsoft upgrades. You pull one string and the whole mess comes apart LOL

I have purposely NOT shimmed the gearboxes on a few of my cheaper stock guns and they still work fine, surprisingly. But when they do go, I doubt I will be able to salvage anything and it would be a new mechbox or a complete gut and rebuild.

[MaciekA]

Originally Posted by ThunderCactus

Honestly if you're not pushing your gears very hard, they can run loose for a long time. It's more critical in helical gears since the nature of their meshing causes axial force.
But if shimming gears didn't improve performance, we wouldn't try so hard to get it perfect in industrial applications.

+1

Pretty much what he said.

I would say the majority of players using guns firing in the low 300s are going to happily continue firing those guns for a long time.

It's when someone like myself or ThunderCactus comes along and poisons their mind with phrases such as "damn, you should really shim those gears, they sound like a dying cat being dragged down the street" that people's hands start to get itchy and they start opening up their gearboxes. Then the arms race for perfection begins. Which I completely endorse

On the other hand, there are a lot of guns being sold that out of the box are starved for torque, poorly-shimmed and are pushing "Canadian import legal" (i.e. >370fps) springs, so out of the box the "what should I do to make this gun shoot well" discussion begins.

Shimming is an important part of that discussion but so is either downgrading the spring or upgrading the power. Hence, again, people like us who are preaching balancing your AEG system with all the usual bullet points.

[SuperHog]

Proper shimming and correct AOE will make any stock gear box last a long long time regardless how low a fps it is running. Every time you pull the trigger, each cycle is brutal on the internals.

[boogiebot]

something about this whole playing with the gearbox really intrigues me. 2 days ago i ventured into breaking down m4 and removing the gear box to change out the spring. I am not gonna lie, definitely not the easiest thing to do and it took MULTIPLE tries to get everything to work properly. I even had to go back to the store and get a little help. overall I am glad to know how to do this and even learned some stuff. but like anything, once you start it can be like opening pandoras box. now i cant stop thinking of other tweaks (like shimming) that could potentially be done to the gun and I have not even go out to play.

[Hectic]

well once you open the grarbox anytime the shimming shoild be checked and adjusted if needed, i hope you at least put the shimms back exactly as they wer when you put it all back together.
useually when you open it up youll first assemble it without the spring and pistin and test that the gears spin freely and dont wobble side to side befor final assembly
rereading my previous posts i may have came across as sayin you dont need shims, u do need shims i was meaning you dont really need to open up most new gearboxes to adjust the shim job.

[boogiebot]

Originally Posted by Hectic

well once you open the grarbox anytime the shimming shoild be checked and adjusted if needed, i hope you at least put the shimms back exactly as they wer when you put it all back together.
useually when you open it up youll first assemble it without the spring and pistin and test that the gears spin freely and dont wobble side to side befor final assembly
rereading my previous posts i may have came across as sayin you dont need shims, u do need shims i was meaning you dont really need to open up most new gearboxes to adjust the shim job.

Thanks Hectic. Yeah when i went back to the store I broke down the gun with them and then put it back together while they watched. I was fortunate enough to get some little tips here and there. But no means am I a pro at this, its just something that I had to learn to do. Just figured that if I am going to play this game I should at least understand how these guns work.

[wind_comm]

Originally Posted by boogiebot

Thanks Hectic. Yeah when i went back to the store I broke down the gun with them and then put it back together while they watched. I was fortunate enough to get some little tips here and there. But no means am I a pro at this, its just something that I had to learn to do. Just figured that if I am going to play this game I should at least understand how these guns work.

we all had to start somewhere. not all of us were birthed into the airsoft world with dual sector gears, frankentorques, massive lipos and r-hops.

[ThunderCactus]

Well since everyones looking at this thread, everyone does it different but here's how I shim a gun;
remove all the internals
put a .1-.3mm shim under the spur gear, then shim it from the top
I just close the mechbox shell and hold it shut myself, and check for axial play and if the gear spins freely
then remove the spur gear
throw a .4-.5mm shim under the bevel and sector gear, and I shim those at the same time
Then throw the whole set in, close the mechbox and put 3 screws in, then check to see if the whole set spins freely

Also important to note, once you re-assemble the mechbox, push back on the air nozzle to see if it moves back and forth freely, just incase you shimmed the sector gear too far into the tappet plate.

And speaking of that, I came in right when everyone was making the switch to NiMH, and the word was to always put stock parts in your gun. Our gunsmithing knowledge was crap back then lol