.25 cal Blod valve strings
I’m using a Talon with a 21″ .25 cal barrel, Blod valve, included heavy spring installed with powerwheel set to 00, stock Talon hammer. Top hat set at .258. Prochrony chronograph. Shooting Kodiaks.
2600 PSI fill
928
928
927
925
925
927
925
931
931
924
926
931
928
925
924
927
920
920
915
897
907
905
899
901
892
882
874
25 good shots
2800 PSI fill
907
922
922
913
917
923
915
943
943
942
938
932
935
935
935
937
942
951
939
939
934
931
948
948
945
938
938
944
937
946
944
937
937
935
931
924
920
922
924
915
915
908
907
910
897
45 shots!!!! Wow. 😯
Going to try a 75 gram hammer when it gets here, but i’m closing in on the bell curve. 😀 Too windy to shoot for groups, but i was hitting my 3″ target at 85 yards with regularity, though i was not really taking my time, and shooting off a bipod, no rear bag. What do you guys think?
All Replies
are the ‘new’ replacement stems thicker? threaded without the stressed currently used?
too thin, too weak….. hope Brad addressed the issues.
😆 He just translated what you said into Spanish… 😉
Looks like he will be getting another stem from Brad through the guy he got the valve from (or something like that)… 😉
I am finally going to get those bits into the post. Work got crazy and it all fell apart from there…
That quote distrubs me, i don’t know what i said i guess. Send it back to whomever you bought it from.
[quote = “stower1”] Uh, yo soy assumig Brad hizo su válvula? En contacto con él en selpharms, esto no es responsabilidad de Blod. [/ Quote]
thanks for the tip, my porveedor in Mexico and send the request for replacement, just wondering if the piece if it is to improve the machining, and correct the thin wall that starts the thread of the stem and factories with the right equipment.
I think if you send a similar piece will end, also broken
if so, to wait for the new part
if not, to send produce to my resources
if not too much to ask, I could count as you did with yours. thanks
Uh, i’m assumig Brad made your valve? Contact him at selpharms, this is not Blod’s liability.
If my machine didn’t have a metric lead screw(Colchester Master square head), id’ve been using it. And would’ve ended up with “anular dwell” as i think its called just the same.
Not sure what those imperial numbers mean in metric.
by the way, why dont you crazy cowboys use metric ? It’s much easier to work in.
I think i use a 6.2mm for the bore of the stems, with around 7mm OD.
I ream the stem hole at 7.2mm.
The steel is 303 free cutting stainless.
It doesn’t give a very good finish as a rule. But is very easy to machine.
I tried 316 at one point. But it felt as if it was “work hardening” as i put a thread on it or bored it. Clicked a lot as i machined it and turned blue.
Later, Sean.
Hello, I also buy the valve blodnob a couple of months and unfortunately I was the same stem was broken, send the photos to the intermediary for a replacement, but apparently has not heard of the manufacturer,
My doubt is whether to improve the piece or simply going to replace the other equal
Thanks
Yeah i would think a run off of the threads is what would help. I have an Ainjest high speed screw cutting attachment to put on an imperial Colchester.
If my machine didn’t have a metric lead screw(Colchester Master square head), id’ve been using it. And would’ve ended up with “anular dwell” as i think its called just the same.
Not sure what those imperial numbers mean in metric.
by the way, why dont you crazy cowboys use metric ? It’s much easier to work in.
I think i use a 6.2mm for the bore of the stems, with around 7mm OD.
I ream the stem hole at 7.2mm.
The steel is 303 free cutting stainless.
It doesn’t give a very good finish as a rule. But is very easy to machine.
I tried 316 at one point. But it felt as if it was “work hardening” as i put a thread on it or bored it. Clicked a lot as i machined it and turned blue.
Later, Sean.
i dont know how the thread was cut. Machine/die.
I use a die in a tail stock sliding tool and as such the die has a taperd lead into it. I believe that would reduduce the stress riser as theres no shoulder on the threads/stem.
Id be happy to remake the affected stems if you dont mind the bugger around of sending them to me to copy.
no charge other than the postage sirs.
hope this helps to put this to bed.
PM sent… 😉
i dont know how the thread was cut. Machine/die.
I use a die in a tail stock sliding tool and as such the die has a taperd lead into it. I believe that would reduduce the stress riser as theres no shoulder on the threads/stem.
Id be happy to remake the affected stems if you dont mind the bugger around of sending them to me to copy.
no charge other than the postage sirs.
hope this helps to put this to bed.
Blod, good you weighed in on this.
Would the threads be better as I suggested earlier to run out as opposed to the sharp end? Also make the wall at a minimum 0.030″ as opposed to the 0.014″ where the are breaking? What of Pabs response earlier?
Were you using SST for the stems?
Regards
Walter…
Te stems do look to be an exact copy in every way.
i dont know how the thread was cut. Machine/die.
I use a die in a tail stock sliding tool and as such the die has a taperd lead into it. I believe that would reduduce the stress riser as theres no shoulder on the threads/stem.
Id be happy to remake the affected stems if you dont mind the bugger around of sending them to me to copy.
no charge other than the postage sirs.
hope this helps to put this to bed.
still trying to settle in the new but old crib
However my brad blod valve well the breech got stuck on the th
With the PW I think that pogo stick of a spring is way too much
I haven’t had much time lately or before to mess with this valve but I think a flat head Breech and no PW And the proper spacer’s
should do
gotta remember this valve was ressurected in the UK
and the AF guns do not have a PW
I will be back soon almost done with the move
Later
SAW
Long time no Saw.
We miss your 3rd person verbal abuse. Get those boxes unpacked and get back online. 😀 😀
Man I hate moving! 👿
Hey TAG Men
still trying to settle in the new but old crib
However my brad blod valve well the breech got stuck on the th
With the PW I think that pogo stick of a spring is way too much
I haven’t had much time lately or before to mess with this valve but I think a flat head Breech and no PW And the proper spacer’s
should do
gotta remember this valve was ressurected in the UK
and the AF guns do not have a PW
I will be back soon almost done with the move
Later
SAW
In truth, standard SS would be fine. 303 maybe. 416 would be plenty strong. 0-1 has superior abrasion resistance, BUT a pain in the ass! First, it likes to micro warp in heat treat. Especially in the quenching phase. There is the slight scale problem even when heat treated in an atmospheric controlled oven. It still gets some scale damage going from the hardening process to quench. This has to be (on such a small-cylindrical precision part) center less ground. So the threads would have to be done before heat treat, and this would be a big issue. And hard to maintain tolerances.
A-2 would be easier to work with but again, over engineered, and with the required extra work, cost prohibitive. Such a small custom run with the heat treat cost and specialized tooling to surface the as heat treated party would make it several times the cost. Trust me on this one guy’s. Its what I do for a living.
Not only that, but the heat treat and subsequent tempering would have t be correct to balance the increased wear against shock. Another advantage to A-2 (and D-2) or Starretts version of 0-1 496 Tool Steel.
Standard non heat treated 303 or 416 is plenty strong, and has good shock resistance. And it isn’t bad about work hardening. It can also be slightly hardened at 1000 f. with no scale issues, while at the same relieving any internal stress. This does not however address the issue of induced stress risers.
There does need t be a gradual radius or taper from the end of the threading cut to the outside diameter of the stem. An easy fix.
This coupled with a slightly thicker wall thickness should do just fine.
I feel for Brad. He has stuck his neck out here. A new product here, with a little growing pains. Not unusual in manufacturing at all. Especially on low volume items. As our T-shirts say, Something abut Air gun Test members (I’m Too lazy to go dig it out o the laundry. I wear it fairly often) 😉
I appreciate Brad giving this a go. It is alway a huge risk bringing out a new product. Especially when it is really a non money maker in the first place. As I understand it, he was just trying to help us out here. And so far, a BIG head ache for him. You have to admire him for sticking with it. I’m sure he has much better things to do.
Brad, If you do decide (out side chance) to go with one of the heat treatable grades, I will be more than happy to take care of that for you.
At No Charge of course! 😉
Mike
- You must be logged in to reply to this topic.
thanks for the tip, my porveedor in Mexico and send the request for replacement, just wondering if the piece if it is to improve the machining, and correct the thin wall that starts the thread of the stem and factories with the right equipment.
I think if you send a similar piece will end, also broken
if so, to wait for the new part
if not, to send produce to my resources
if not too much to ask, I could count as you did with yours. thanks
Let me try to clear things up. English translation in (bold)
rov_box: Voy a tratar de traducir lo que necesitas para ver si alguien del foro te puede ayudar. (I’m going to try to translate what you need to see if someone in the forum might be able to help)
¿A quien le compraste la válvula? (Who did you buy the valve from?)
No hay proveedores de la vávula blodnob en Mexico (There are NO suppliers of the blodnob valve in Mexico)
Si tu válvula es estandard, hecha por AirForce, entonces debes reclamarle al distribuidor que te la vendió. (If your valve is stock, then you should make your claim with the distributor that sold you the valve)