swiss cheesed? i beg you pardon!

[EBR-freak]

i work in the armoury at my local airsoft site and do a lot of gearboxes and have been doing for 3 years. but all of a suden out of the blue on this forum i saw the term 'swiss cheesed'. i am officialy confuzzled. may someone hel;p me out by explaing this new term???

[screwdriver]

Re: swiss cheesed? i beg you pardon!!

a name for drilling holes in the piston to reduce weight

[Blackwell]

Re: swiss cheesed? i beg you pardon!!

Swiss Cheesing:

Drilling holes in the piston in order to reduce its weight and improve rate of fire.

After completion said piston looks like "swiss cheese" because of the holes.

Simples!

P.S. too much holes and the piston will destroy itself :p

[EBR-freak]

Re: swiss cheesed? i beg you pardon!!

i see. thanks very much screwdirver

[EBR-freak]

Re: swiss cheesed? i beg you pardon!!

and blackweel tah

[Blackwell]

Re: swiss cheesed? i beg you pardon!!

Gah beaten to the post.

My bloody long descriptions.

[Stones]

Re: swiss cheesed? i beg you pardon!!

so if I drill holes into the piston i could increase the rate of fire. interesting, not that i'm going to try it. My motor in my rifle is kinda exploding with this new battery, don't need any more problems.

[Blackwell]

Re: swiss cheesed? i beg you pardon!!

Tbh swiss cheesing is something I'd do as a last resort to increasing my rate of fire. You'd be surprised how much a good shimming and a MOSFET can do for the ROF.

And the fact the piston is plastic, I wouldn't expect it would last for long with a bunch of holes in it.

[screwdriver]

Re: swiss cheesed? i beg you pardon!!

personally you have two choices.
1/ high speed gear set up.
2/upgrade to a 9.6v and use a lower fps spring.
3/ swiss cheesing the piston will only be worth the hassle once you have carried out option 1&2

[Stones]

Re: swiss cheesed? i beg you pardon!!

I might get a new less powerful spring for mine, altough I can't get my gearbox out as the damn rear bolt wont budge at all.

Current spring is firing about 338 odd with a tightbore. I'd like to get it down to about 320 odd.

[omgitzjamiiee]

Re: swiss cheesed? i beg you pardon!!

Also shaving of a few off the teeth on the piston can increase ROF.

Don't hold me to that though.

[screwdriver]

Re: swiss cheesed? i beg you pardon!!

wont increase rof but will prevent pre engagement on a high speed set up

[dope_on_a_rope]

Re: swiss cheesed? i beg you pardon!!

Swiss cheesing, and taking the last teeth off the piston in a short stroked sector gear gearbox, wont make the rof measurably faster. The idea is, to allow the piston to return to battery quicker, to reduce the chances of pre engagement. Shaving down the second tooth from the pick-up end is also intended to reduce the lightly hood of pre engagement. Although removing that tooth has now become a necessity anyway in a high rof set up, because most people will either stack the cylinder head or shim the piston for a better angle of engagement. If you're going to Swiss cheese your piston, one would hope you've got a polycarbonate piston, with any excess teeth already removed, and a polycarbonate non bearing, but ported piston head. And have stacked some material on the cylinder head as well (rather than adding weight to the piston by shimming that).

I wouldn't even consider Swiss cheesing in anything under a 30rps gearbox. Even then a bigger spring and a shorter piston travel will probably be a better method. Unless you're talking about a very long barrelled gun.

Edit: Even after I've given all that dribble. I'm not convinced the ROF at which pre engagement will happen is likely to be much effected by the weight of the piston. I'd be much happier with the big spring short stroke method. As not only does this speed up the time the piston returns to battery, but also gives you more rotation of blank teeth on the sector gear. And just having a shorter barrel can allow you to run a faster gun. The quicker the BB has left, the less pressure is on the piston and the faster it travels. Conversely, if your BB decides to jam in a high rof set up, you'll get a bit of an airlock in the cylinder, and pre engagement can happen then. This doesn't necessarily have to totally jam the BB. The BB might still clear the barrel, but slower than normal, and that can lead to the piston stripping.
I've heard reports of CA m249s run at high rof. When the hop was set too high, it would jam the BB and strip pistons in this exact way.

[richardy]

Re: swiss cheesed? i beg you pardon!!

exactly what dope said... the others are wrong im afraid, well mistaken

its for timing only to help when premature engagements an issue. which happens to be when increasing ROF.

[jfox61]

Re: swiss cheesed? i beg you pardon!!

I've heard reports of CA m249s run at high rof. When the hop was set too high, it would jam the BB and strip pistons in this exact way.

Hand up in the air for that one. Happened to me a few weeks ago.