Need help with a pin down screw for Boss valve…
…does anyone know where I can get one, or what size it is so I can begin searching the hardware stores????
It is larger then the size on the stock crosman valves…I am surprised B&A did not include one when I ordered my valve from them.
This really stinks as I was all set to compare three valves in the same carbine (everything else the same)
I have crony results from a Roy (Mountain Airguns) valve in my 14″ barrel 2250…and I wanted to compare them to the Boss valve numbers and a Discovery valve numbers (which by the way requires a different size pin down screw as well 😡 ).
Thanks guys.
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Viewing 12 replies - 1 through 12 (of 12 total)
80,
Thanks very much for that information. Will be giving them a call tomorrow sometime.
Geesh this stuff is like soooooo addicting…
Carl
Are you going to flow-mod the disco valve that you’re going to test, or is it going to be in stock configuration?? Since I’ve got one on order, I am naturally very curious of your results, and will be watching for updates here!! 😆 😆
I’ll test it in stock form and see how it does…then I will “flow-mod” it and compare results. I made a temporary 8-32 screw this morning that will work for testing purposes ….Hopefully I will get to do some testing in the morning, if not, Tuesday is my day off and I will go at it then.
I have a brand new, never been fired valve sitting on my bench..it is out of the 2260 that I’m converting to hpa.. BRAND NEW!! It measures 64.14mm…the BOSS stem is sticking out a little bit farther due to the fact that the valve stem seat is lowered a wee bit, this naturally allows stem to protrude out the back farther..The MA valve that I got, did not have any material removed from the seat, so it was shorter too, when compared to Boss. I use a Disco stem in my 2250 HPA gun valve, it’s overcoated and already comes without the piercing end 😀 😀
Are you going to flow-mod the disco valve that you’re going to test, or is it going to be in stock configuration?? Since I’ve got one on order, I am naturally very curious of your results, and will be watching for updates here!! 😆 😆
closer to the hammer will indeed reduce hit so you may need to shorten the stem….. if the stem is closer to the hammer that is. Did you measure teh valve body or the stem to determine this?
I like a TP hole size of 0.156″ for .22 cal and a counterbored poly tube seal. The seal is then well supported and surrounded by metal so it only has to be about 0.005″ longer than the cavity. I do not like the poly tube made any other way as then the breech screw takes a beating and the poly tube can collapse into the TP.
For the PCP conversions i use 3 8-32 SHCS and for CO2/HPA only the one
Good luck with it
keep us posted
Walter….
Walt, I measured all of them with the stem installed in the body….So I measured from the end of the cap where the co2 cart seats against the valve…to the end of the valve stem.
If I had to cut the valve stem I would need to pick up an extra one as I only have one…if that is the case..I may have to wait on testing the Disco valve…
Incidentally, the Disco valve body is actually longer than the other two…but since the internal depths are different the valve stem doesn’t penetrate the valve body as deeply as it does on the Boss valve…giving the boss valve and stem the longest lenght of the three.
Sorry for the metric…I will measure in standard in the future. As for the TP…you instructed me about this already and I counter sunk one of my MA valves in this manner as per your advice…thanks again.
Talk to you later!
Carl
Here you go Carl. Call Ron and talk to him…he is a real nice guy and will help you with your needs. I only bought the valve body not an entire valve as I had all the other parts I needed. I think it was 15.00
80, sorry don’t do too well with metric 🙁
closer to the hammer will indeed reduce hit so you may need to shorten the stem….. if the stem is closer to the hammer that is. Did you measure teh valve body or the stem to determine this?
I like a TP hole size of 0.156″ for .22 cal and a counterbored poly tube seal. The seal is then well supported and surrounded by metal so it only has to be about 0.005″ longer than the cavity. I do not like the poly tube made any other way as then the breech screw takes a beating and the poly tube can collapse into the TP.
For the PCP conversions i use 3 8-32 SHCS and for CO2/HPA only the one
Good luck with it
keep us posted
Walter….
80, where did you pick up the Boss valve? I am just now beginning to modify my newly acquired, bone stock 2240 and looking for a few improvements. Nothing too major just some subtle ones.
Carl
just for interest sake the upsize by Boss to the 8-32 was a result of my rec’d to their machinist. Prior to that change they used the wimpy Crosman 6-40 screw. 🙂
Walt, I should have known you had something to do with that 😆
Looks like Crosman caught on to your rec’d as well. I was wrong in saying their valve was a different screw size…It is the same as the Boss (8-32). 😳
I don’t have an end mill so I will have to shorten the screw the old fashion way…thanks Walt.
Walt, another thing I have noticed is that the boss valve (when completely assembled in 12gr cart/strike pin form) measures 65.90 mm. The Disco=64.52mm and the MA (Roy)—which I assume is stock Crosman lenght—is 64.32mm. This will put the valve stem on the boss valve 1.58mm closer to the hammer strike point. Won’t this have an effect on duration and such??? Please let me know.
Also, the Transfer Port openings vary as well. Roy’s modified Crosman valve was the largest measuring 5.03 mm i.d. 4mm for the Boss, and 3.90 for the Disco.
Shot count on Roy’s was low as expected with a huge plume of Co2 exiting the muzzle on my 14″ test barrel. Shot count with 14.3gr CP
558
561
559
555
557
561
569
563
565
567
565
555
559
553
549
546
536
I will be curious to see the variation in fps between the three different valves. Walt, what do you deduce will happen with the longer Boss valve? Thanks for all your wisdom!!!
Packrat,
I will try to get to HD or Lowes today to get some screws…That build of yours sounds awesome. Can’t wait to see the progress. I have all kinds of ideas! If only I was a machinist. Being an artist I have all this vision, but alas I am limited by my crude tools and skills. I will draw plans and hope to delegate out the machine work.
You can always use the “grub screw” approach….6-32 or 8-32..the 2250B that Roy built for me came with 1 screw , on r/h side, I added one to l/h side, more “insurance”.. although, using the “internal” screw does make for a cleaner look, not having holes drilled through tube!! just something to consider.
I am currently building a 2260 HPA gun (with AR2078A wood stock) using COMPLETE disco tube and internals..I would be VERY interested on what you find out with the 3 different valves.I’ve already modified a new 22XX series valve ( using the B&A valve as my pattern), but could always change my mind and use a disco, if it were to show better flow/power characteristics…..still waiting on some of disco parts from Crosman, so would be ideal time for me ….SO< PLEASE POST YOUR RESULTS !!
80, I use 8–32 low head SHCS as they have the right head size to fit the tube and the head is 0.090″ thick IIRC. I use an endmill and set the head into the valve body 0.025″ deep.
just for interest sake the upsize by Boss to the 8-32 was a result of my rec’d to their machinist. Prior to that change they used the wimpy Crosman 6-40 screw. 🙂
I just found on their sight that it says they are 8-32, but now I need to find those with a small “flat” head size to clear the trigger assembly….
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Thanks very much for that information. Will be giving them a call tomorrow sometime.
Geesh this stuff is like soooooo addicting…
Carl
No problem…check out my other post, “…22xxx valve comparison”. I tested the Boss Valve and I was pleased with its performance!