Grinding down piston rails. V2
 

The piston rails in my king arms v2 gearbox and ICS upper gearbox are just a little too raised to take any of the several SHS/Rocket airsoft pistons I have. I have a variable speed dremel but I am unsure which accessory would be optimal for the task at hand. I don't have access to a vice so the angle I must approach the rail might be challenging. We can't touch the walls. Any advice or recommendations are appreciated.

Dremel down the piston not the gearbox. You can make the piston slightly lighter in the process while not damaging the gearbox.

You can replace the piston for $10 but it will cost $50+ for a new gearbox.

The polycarbonate material pistons are made of are easily removed with rough grit sandpaper. I would rather you make the rails of the pistol. Thinner than Dremel the rails on the gearbox. That's just my take on it.

I considered that. I should have mentioned I am using the 14 metal teeth (all 3 are the same) factory lightened piston. So material is already removed and where I would be removing it from it's already kind of thin, I am concerned about the structural integrity of the piston. I will be using it in a trigger response build with 12:1 gears/HT motor and M110 spring.


https://cdn.shopify.com/s/files/1/14...g?v=1472091169

Using this exact one. If removing sanding/filing the piston is simpler I would rather do that. Is it feasible?

No there shouldn't be any problem.

Building engineers and architects often use a triangle design for it's support beams because the 3 sides often redistribute the force evenly to prevent damage. The way that the force is distributed here is like hammering the top of a triangle so that the other sides redistribute the force to prevent it from cracking in half.

The force of the piston head is absorbed at the front whereas the sides are just for guides. The stress of the material wouldn't be at the rails and if you look at pictures of common points of failure you would know that the piston breaks either at the front or the end usually where the piston hits the cylinder head or where the pickup tooth sustains too much stress from pre-engagement. As long as you don't dig into the trench of the rails it will be fine. Just take a bit off the inner sides of the rails rather than digging deeper unless it really is that fat.

you'd be fascinated to see how light some DSG builds get their pistons without any fear of breaking.

It definitely was a better idea to file down the piston rather than GB rails. I did have to file down the trenches a bit, but not enough to compromise structural integrity. The piston trenches were not deep enough to allow it to sit properly with GB closed. Thanks again.

+1 for filing down the piston. If you want to do anything to the rails, take some 1000 grit sandpaper to it just to remove any burs or minor high spots. Beyond that I wouldn't touch the rails though.

An upper gearbox shell for ICS or a gearbox shell for a regular V2 is a lot more expensive to replace than a piston.

I have one of those same pistons in an ICS M4 I built for indoor play, and the piston needed some light filing + sanding to work well.

I'd file down the rails, but I'm confident I can do it properly.
How confident are you that you won't fuck up a mechbox shell?