Shimming : how freely should the gears move?

[Silverthorn]

Hello,

I just started getting my hands dirty with shimming. I've read many things, looked at some pics and vids and "finished my first job". I got the basics (maximize the contacts of the teeth between gears but avoid friction between gears and avoid lateral movement of the gears in the mechbox).

I have shimmed a v2 mechbox with high-speed modify gears and modify shims.

Once the gearbox closed and the screws installed, how freely should the gears turn when I give them a spin?

Right now, when I give them a spin with a screwdriver they spin maybe a full turn or so before stopping. Is that enough or is it too tight?

Thanks!

[Crunchmeister]

The gears should turn freely with no resistance at all with as little side-to-side play as possible.

[Silverthorn]

Originally Posted by Crunchmeister

The gears should turn freely with no resistance at all with as little side-to-side play as possible.

Yeah but I was wondering about the definition of the word freely :

1. When you turn them with your fingers, it's easy. No resistance.

or

2. When you give them a strong spin, they spin "freely" for 3-4 full turns or is 1 turn sufficient?


or a mix of both?

[AngelusNex]

Originally Posted by Silverthorn

Yeah but I was wondering about the definition of the word freely :

1. When you turn them with your fingers, it's easy. No resistance.

or

2. When you give them a strong spin, they spin "freely" for 3-4 full turns or is 1 turn sufficient?


or a mix of both?

More so 1 as 2 depends on how hard you spin them. if it spins freely on it's own after a little spin and doesn't just stop once you let go it's good.

[Blackthorne]

It depends on the condition of the parts you are putting in:

If everything is brand new, the "one turn to stop" you described would be fine as there will be some wear as the new parts break in.

If everything is (or some parts) are older then adjust accordingly. My SystemA box has about 5000 rounds through it and I can get at least 4 or 5 rotations out a good push with my finger.

A little more resistance with less lateral/shear is a better trade off than a freely spinning set of gears that have play/wobble.

[Crunchmeister]

I'd say a mix of both. Because of the nature of multiple gears working together, you probably won't get more than 1-2 free spins at the very most. At least for me, that's been the way shimming has been working out. My Modify modular gear sets seem to work that was as well with their 'perfect shimming', so short of a gun doc telling me I'm not shimming properly, I believe that's correct and that you have it done right.