I was recently working on a airsoft bolt action sniper, and ran across a fabrication problem. As you can see, the piston is exactly like those found in commercial airsoft springers. The entire piston cylinder is pulled back, until the piston rod catches on a sear. Then the cylinder is moved back to the barrel. The piston rod is then released, leaping forward and creating a quick, high pressure burst of air which propels the BB. So far so good.
My problem was coming up with a case for the entire assembly.
I had intended to place the 3/4 inch PVC cylinder inside a slightly larger pipe with a slot in the side for the charging handle. Unfortunately, I was unable to find a pipe with an inside diameter of the correct size.
Any idea's on creating a case for this?
I thought of a block of something (steel, aluminum, wood, epoxy) with appropriate sized holes bored through, but I lack the tools to do a really good job of it. The problem is that the nozzle has to end up in a very specific place each time, and any variation could cause rapid wear.
Posted: Wed Apr 17, 2013 10:47 am
by jrrdw
These plus this and some of this you should be able to get it done.
Posted: Wed Apr 17, 2013 10:52 am
by mako
Yeah, I'd thought of that. I'd use oak, or something harder, but I didn't know if the wood would stand up to that kind of wear. Also, I have a drill press (old but in good shape). The biggest problem is getting the holes to go exactly straight.
Posted: Wed Apr 17, 2013 11:28 am
by jrrdw
Use a 3/4" steel washer for a stop to prevent wear. Do you have a vise on your drill press? A tilt table? A combination square? If you have those tools you should have no problem drilling any angles or straight holes. I have that exact set of spade bits, for cheep-os they are surprisingly good.
Posted: Wed Apr 17, 2013 11:32 am
by mako
The wear problem would be on the hop-up chamber nozzle, but if the hole is exact its not a problem. And no, there's no built in vise on the drill press or a square, but I guess I could fabricate a jig for that. And spade bits aren't too hard to lay hands on.
Posted: Wed Apr 17, 2013 12:02 pm
by jrrdw
jrrdw wrote:Use a 3/4" steel washer for a stop to prevent wear. Do you have a vise on your drill press? A tilt table? A combination square? If you have those tools you should have no problem drilling any angles or straight holes. I have that exact set of spade bits, for cheep-os they are surprisingly good.
Well I worded that wrong. Do you have a vise for your drill press? And a combination square?
Hey, thanks, man. 8) I didn't realize they made those.
I could use that. Have you ever used a drill press on aluminum block?
Posted: Wed Apr 17, 2013 12:23 pm
by jrrdw
I used my drill press to drill the equalizer holes on this piston I made for another SF member. I tilted the table with the vise I showed you. Bolted my vise to the table, tilted to about 45 degrees and drilled 3 holes in it.
[youtube][/youtube]
Posted: Wed Apr 17, 2013 12:25 pm
by mako
Nice piece of work, mate! I'm impressed. I guess maybe I'm not as limited by the tools as I thought I was.
Posted: Wed Apr 17, 2013 12:45 pm
by jrrdw
You can do a lot with a drill press. If my camera hadn't broke I was going to get a video of me drilling the EQ holes but I wanted you to see the aluminum piston so you know you you can use what you have. I hope it helps.
Posted: Thu Apr 18, 2013 4:00 am
by Crna Legija
were you from? if you can't do it, put a post in here and maybe someone can help you!
Posted: Thu Apr 18, 2013 4:33 am
by Zeus
Crna, if we're taking bets, I'll guess New Zealand, airsoft, but using mate
If you're within a fair shipping distance of Aus, I'll gladly run something up when this lathe comes in
Posted: Thu Apr 18, 2013 7:10 am
by Crna Legija
yeah that why asked though he might be aussie, hahah if you are draw what you need and ill see what i can do!
Posted: Thu Apr 18, 2013 1:03 pm
by mako
Sorry, guys, not Aussie. Good old Lone Star State. I can't stand the standard use of the word "Dude", so I use "mate". @Crna Legija, I can make the stuff myself, but I wanted to know if there was an easier way to go about it.
Posted: Thu Apr 18, 2013 3:56 pm
by cammyd32
You could cast a casing using casting resin, I think Jsr recently posted quite a good link about casting resin somewhere, I'll see if I can find it...
You could put your pipe inside a polystyrene mold and fill it to the top with high strength resin wait till it cures and remove the mold, then hey presto, you have a solid completed housing encasing your spring-plunger setup, no complicated drilling required, and if you cure it right, it's clear, so you can look inside to see your mechanism working
