Search found 1943 matches

by JDP12
Sat Mar 31, 2012 3:16 pm
Forum: Pneumatic Cannons
Topic: Semi-auto 800 PSI .51cal WIP
Replies: 68
Views: 16293

haha yeaa it does look better. yea i'll have to lengthen it. that close nipple is actually epoxied into the bushing, so i'll probably have to add a coupling+ nipple, or i'll use a female x male adapter. depends on how much room I need to add. Looks like I'll have to add 2-3". Gonna cut down on the d...
by JDP12
Fri Mar 30, 2012 11:38 pm
Forum: Pneumatic Cannons
Topic: Semi-auto 800 PSI .51cal WIP
Replies: 68
Views: 16293

Yea ramses is machining for it me here in country.. thankfully. Ran into another issue... Chopping up a nerf gun for the handle and trying to figure out its placement. All the yellow part will be cut off, it'll pretty much just be the black portion of the handle. I was originally hoping to tuck it r...
by JDP12
Thu Mar 29, 2012 10:31 pm
Forum: Pneumatic Cannons
Topic: Semi-auto 800 PSI .51cal WIP
Replies: 68
Views: 16293

Got the brass elbows today.. they were pricey but after assembly, definitely worth it. It may not look like much, but it definitely compacted the gun a significant amount in my opinion. Finally got bolt dimensions worked out, so ramses will be making that for me this weekend and shippin it here. Sti...
by JDP12
Thu Mar 29, 2012 2:21 pm
Forum: Pneumatic Cannons
Topic: need advice on floatin o-ring
Replies: 14
Views: 3237

Sorry for the bump.. but i measured in a couple different spots.. and I've gotten .50, .51, and .52.. lol
by JDP12
Thu Mar 29, 2012 1:34 pm
Forum: Pneumatic Cannons
Topic: need advice on floatin o-ring
Replies: 14
Views: 3237

lol yea I have some .5" OD o-rings on the way, time to update the drawings for the umpteenth time for ramses. calculating about 10% o-ring compression.
by JDP12
Thu Mar 29, 2012 12:36 pm
Forum: Pneumatic Cannons
Topic: need advice on floatin o-ring
Replies: 14
Views: 3237

WAIT... ok, so on a whim i decided to measure the diameter of my barrel again. Turns out its not .527" like mcmaster said, but .500". So.. if I just get an o-ring with OD of .5", should be able to easily make the groove. Seems like problems solved... guess I should follow the measure twice rule a bi...
by JDP12
Thu Mar 29, 2012 11:13 am
Forum: General How-To & Discussion
Topic: How to: semi-auto airgun for beginners
Replies: 36
Views: 15637

Nice tutorial, I have a couple of those QEV's and slide valves myself..I like them personally, using a slide valve to vent my piston valve right now.
by JDP12
Thu Mar 29, 2012 10:24 am
Forum: Pneumatic Cannons
Topic: need advice on floatin o-ring
Replies: 14
Views: 3237

Thanks Tech, I'll have to custom make an o-ring now I guess.

Just waiting to hear from Gippeto.
by JDP12
Wed Mar 28, 2012 11:51 pm
Forum: Pneumatic Cannons
Topic: need advice on floatin o-ring
Replies: 14
Views: 3237

I told ramses (who is machining this for me) that I need 20 hours to figure this out because he pretty much has to get it done this weekend and I don't wanna delay him any more than necessary. EDIT: my calculations were relying on o-ring compression of 30-40%, which is a significant amount. looks li...
by JDP12
Wed Mar 28, 2012 11:33 pm
Forum: Pneumatic Cannons
Topic: need advice on floatin o-ring
Replies: 14
Views: 3237

yea i need the bolt to seal into the barrel. It sort of does have to act as a check valve i suppose. Since the air is actually coming into the barrel ahead of the o-ring it has to keep air from going backwards.. dunno if that makes it qualify as a check valve or not. That was my original plan, but t...
by JDP12
Wed Mar 28, 2012 6:31 pm
Forum: Pneumatic Cannons
Topic: need advice on floatin o-ring
Replies: 14
Views: 3237

Ok, so right now I drew it out so that the diameter of the o-ring groove is .3775", which is .06" less than the ID of the o-ring. Is this too small? Should I make it just barely smaller than the o-ring or will this suffice?
by JDP12
Wed Mar 28, 2012 4:50 pm
Forum: Pneumatic Cannons
Topic: need advice on floatin o-ring
Replies: 14
Views: 3237

need advice on floatin o-ring

So as I was talkin to ramses about machining my bolt, he proposed that I should use a floating o-ring, which i had not thought about. I've never used floatin o-rings so I could use some advice. The barrel ID is .527". Currently I have .5625" OD o-rings, and thats the closest I can get without going ...
by JDP12
Wed Mar 28, 2012 4:04 pm
Forum: Pneumatic Cannons
Topic: Semi-auto 800 PSI .51cal WIP
Replies: 68
Views: 16293

I don't see how that would do anything.. the mag block has female threads so that would make it even worse. These are NPT threads, not BSPP so I can't thread them infinitely.
by JDP12
Wed Mar 28, 2012 3:51 pm
Forum: Pneumatic Cannons
Topic: Promethean rifles
Replies: 18
Views: 3874

thats awesome man, glad to hear it. you're doing some impressive work and inspire me to keep workin and makin things better!
by JDP12
Wed Mar 28, 2012 3:03 pm
Forum: Pneumatic Cannons
Topic: Promethean rifles
Replies: 18
Views: 3874

your 19? Damn thats impressive.

I'm 19 and would kill to have that sweet of a machining setup.