GTA
All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Show us your Custom Airgun Parts (TRICKS-N-TIPS) => Topic started by: happymecanic on July 23, 2021, 08:06:55 PM
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I just built a small 4500/850 psi mini bottle for a QB project. I used a First Strike 4500/850 regulator: https://first-strike.com/content/First-strike-HERO-45k-manual-final.pdf (https://first-strike.com/content/First-strike-HERO-45k-manual-final.pdf) , and an AGH water/oil filter/separator tube and caps: https://www.aliexpress.com/i/32960501720.html (https://www.aliexpress.com/i/32960501720.html) . The tube has about 80 cc or 4.9 cu. in. of volume, and the reg has indexable threads so I can turn it in the most favorable position. I had to drill and tap one of the caps for 5/8''-18 NF threads for the regulator, with the other cap I was lucky. I just had to use my 10-32 tap, as the hole was exactly the right size for these threads. I used a SS screw and a new delrin seal to seal the hole. I filled to 3800 (my main tank is not full), no audible leaks, I'll see tomorrow how it does. This will make a very sweet and compact power package for my QB carbine!
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Sweet results ... Going IN-LINE on a 78 or dropped on a 79 ?
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Sweet results ... Going IN-LINE on a 78 or dropped on a 79 ?
Almost IN-LINE, with just a small drop, on a 78D .22 . Need to drop about 1/8'' to clear the 15 mm barrel. This is a parts gun with a chopped (butchered) barrel I got for 30$. I made a new stock in cherry wood, bought a few missing parts, and I'm now converting it to HPA. It'll have a 9-shots self-indexing magazine (from Europe), and a Discovery VT-3 4-16x44 FFP SF scope. :D
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Hmmmm, 2250B with mini HPA bottle :D. Need to make two drop blocks ;D.
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Nice job.... Those are interesting low-profile burst discs.... 8)
Bob
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very cool , and looks factory
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I have one of them filters just sitting around, every time I look at it, think that could make a great pressure vessel, never thought to regulate it. 8)
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Nice job.... Those are interesting low-profile burst discs.... 8)
Bob
Thanks guys!
Bob, the burst discs are made by Guerilla Air, I saw them in 1.8, 4.5 and 7.5k ratings: https://www.pbsports.com/collections/gas-systems/products/guerrilla-air-7-5k-pro-burst-disk. (https://www.pbsports.com/collections/gas-systems/products/guerrilla-air-7-5k-pro-burst-disk.)
Nicest thing is that the measured width over the burst discs (1.369'') is just 0.010'' smaller than the tube's diameter (1.379''), this can make for very clean builds 8).
I checked the pressure gauge this morning, same exact pressure as yesterday, everything seem to be holding up fine :D.
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That looks great (including the stock!). How thick is the end cap that was threaded for the regulator? This required a groove for the o-ring (fancy chamfer) correct?
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That looks great (including the stock!). How thick is the end cap that was threaded for the regulator? This required a groove for the o-ring (fancy chamfer) correct?
Thanks Eric!
If you mean the length of the cap it's 30 mm (about 1 3/16''). The regulator threads are 25 mm in length, so it's screwed in its entire length. And yes I had to cut a groove for the Oring. I don't remember the exact dimensions but I measured the installed Oring OD and cut the groove ID 0.010'' smaller. The depth of the groove (or its length) is the thickness of the Oring + 0.010''. I carefully chamfered and polished all edges, the fit is excellent and there's no leaks. Check my next post for a picture of the valve front half/adapter, you can see a similar groove I made to seal with the back half ;).
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Today I finished the parts/mods needed to use the mini HPA bottle on my QB78D. The tube no longer sees pressure, the HPA is entirely contained in the valve/adapter assembly.
I made the front valve half in 316L SS with a machined pocket for the spring end, and machined a 0.030'' deep shoulder for the spring to seat on the poppet.
The receiver tube is cut to 7 7/8'' in length (stock one is 14 7/8'', QB79 is 11 7/16''), so the front of the valve exits the tube, and the ASA fitting screws directly on it. The entire tube/valve/regulator/bottle assembly is 19 1/8'' in length.
The entire assembly holds pressure very well, no leaks detected after a 30 seconds dip in a five-gallons bucket full of water.
Last pic shows a montage of the parts to give an idea of the ''finished product'' ;). Barrel length: 14'' of rifled bore starting at the TP, total length of the rifle 33 1/2''.
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Very well done and a great use for something that already is rated for HPA.
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What is your total plenum/valve volume, downstream of the regulator?....
Bob
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Very well done and a great use for something that already is rated for HPA.
Thanks Matt! Why not when it's easy and affordable? :D The regulator cost me 50$ Can, and the filter about 15$ (got it bundled with my HPA compressor). I have scrap metal and a good lathe, and I'm on vacation for two weeks ;D.
What is your total plenum/valve volume, downstream of the regulator?....
Bob
Bob, the valve has the same volume as a stock one, and add a 3.5 mm ID x 25 mm long air passage. Sorry for not being more precise, I don't know the volume of a stock QB valve :-[. It would be easy to machine a much bigger plenum , or to add one between the front valve half and ASA fitting in my current setup.
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Plenum size required depends on your hoped for FPE.... 1cc/FPE is ideal, you can get away with half that.... I think a stock QB valve is about 6-7 cc....
Bob
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Plenum size required depends on your hoped for FPE.... 1cc/FPE is ideal, you can get away with half that.... I think a stock QB valve is about 6-7 cc....
Bob
Well I should be good then, this gun is destined to stay as a non-PAL airgun 8). A .22 15.89 grains pellet flying @ 450 fps makes 7.15 ft-lbs. Thanks for the info on the valve volume!
Today I finished the ''fitment work'' required with the addition of the mini-bottle. I slightly miscalculated the clearances between the barrel and bottle at first, was off by about 0.060''. I solved the issue by turning the barrel's OD down from 15 to 12 mm. Now there's about 0.030'' of clearance between the barrel and tank. Love them low-profile burst discs ;D.
I can't shoot the gun right now as the innards are out of the gun, but a light tap on the valve stem gives a good bark :D . Just can't wait to shoot it again! Accuracy was great up to 35 yards with 12 gr CO2 cartridges, I'm impatient to see how it does on HPA.
I'd like to go rather deep into the tuning and build of this gun, so I'll start a new thread on the build rather than adding more non-specific datas here. Thanks for the help and interest guys! To be continued... :D
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Nice work.
I had no idea these tubes were available.
Gonna have to pick one up to play with.
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Nice work.
I had no idea these tubes were available.
Gonna have to pick one up to play with.
Thanks Ron!
I saw a shorter one on Ali, 170 mm long (about 6 5/8''). Would be nice on a 13xx/22xx conversion:
https://www.aliexpress.com/item/4000618680690.html?spm=a2g0o.productlist.0.0.49f573a1owvaBg&algo_pvid=47d13b0a-ba08-45e0-a279-9a382c9808ac&algo_exp_id=47d13b0a-ba08-45e0-a279-9a382c9808ac-13 (https://www.aliexpress.com/item/4000618680690.html?spm=a2g0o.productlist.0.0.49f573a1owvaBg&algo_pvid=47d13b0a-ba08-45e0-a279-9a382c9808ac&algo_exp_id=47d13b0a-ba08-45e0-a279-9a382c9808ac-13)
Shipping cost is ridiculous though.
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Picked up this one on EBay.
Think it would be good to use for a regulated PRod.
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Picked up this one on EBay.
Think it would be good to use for a regulated PRod.
That should do :D. And you get a spare hose, fittings and cotton filters!
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Got mine done.
This one is right at 6 CI.
Just need to procure a PRod to put it on.
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Nice and clean work! What kind of a regulator did you use?
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Picked up this one on EBay.
Think it would be good to use for a regulated PRod.
cant find the black ones , have a link?
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Picked up this one on EBay.
Think it would be good to use for a regulated PRod.
cant find the black ones , have a link?
WesBob has them also IIR where I got mine.
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This is the one I purchased on EBay.
https://www.ebay.com/itm/324622331739?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649 (https://www.ebay.com/itm/324622331739?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649)
Wish you could just buy the tank without the extra filter media etc.
Would be more reasonable.
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Nice and clean work! What kind of a regulator did you use?
It's a Tippmann reg.
Cost about $25.
https://www.ebay.com/itm/383786032733?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649 (https://www.ebay.com/itm/383786032733?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649)
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thx Ron thats a pretty good deal.
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Here's what mine looks like on a PRod "short block".
More here:
https://www.gatewaytoairguns.org/GTA/index.php?topic=190314.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=190314.0)