Oh come now busta... every good airsoft tech junkie should be able to understand and use a vernier caliper. The least amount that you put together and take apart your gearbox the better. Taking your gears in and out, screwing and unscrewing your gearbox, is a good way of stripping out the little thread holes. Busta is right, you should make sure the gears spin with the correct amount of shimming but do what he said once in the life of your gearbox and only then after great consideration. Busta, perhaps you should elaborate on what a correct fit should feel like?
The way I make sure mine are tight but not too tight is to put it together gear by gear like I said, but, put your thumb on one bushing onthe outsides and another finger on the otherside, there should be little to no play, but when sticking a small jewelers screw driver or a finger in there, the gears should spin freely and smooth.
Well, I used a dial indicator last time I shimmed, but not everyone has access to 376 dollar precision instruments when upgrading their mechbox.
Honestly, as long as they are not loosy-goosy, you should be good to go. I played with an upgraded box for 1 year before I even bothered to shim and had no problems. I mean, this isn't aviation. . .
