BARGAIN ALERT WITH LINK

[nervoustrig]

The way I like to think of it is this...

With a tall series Belleville stack, a small change in pressure produces a lot of piston travel. Meaning after you take a shot and the pressure is recovering back up toward the desired setpoint, the piston is closing in toward the valve seat. The last little bit of the piston's travel is trying to pinch off an infinitesimally small gap to halt the pressure rise at the intended pressure. It will therefore tend to equalize to a more consistent pressure from cycle to cycle...even if the washers shift a little bit relative to each other, or the materials expand or contract a little with temperature, or some other variable intrudes.

 

[UCChris]

The way I like to think of it is this...

With a tall series Belleville stack, a small change in pressure produces a lot of piston travel. Meaning after you take a shot and the pressure is recovering back up toward the desired setpoint, the piston is closing in toward the valve seat. The last little bit of the piston's travel is trying to pinch off an infinitesimally small gap to halt the pressure rise at the intended pressure. It will therefore tend to equalize to a more consistent pressure from cycle to cycle...even if the washers shift a little bit relative to each other, or the materials expand or contract a little with temperature, or some other variable intrudes.

That's a great explanation, thank you!

 

[UCChris]

Got my two 15ci tanks. Haven't put them on the scale, but the 15ci tank feels like it's less than half the weight of my 13ci aluminum tank. The 15ci + regulator feels almost exactly the weight of my 9ci tank sans regulator.

If I can get the regulator off one of the 15ci tanks, its going on my .177 QB. If there's a way to bump the setpoint to 1500ish with Bellevilles, the other 15ci will go on my wife's Prod bullpup. Super excited!

 

[nervoustrig]

Note to self: finish up McMaster cart tonight...

 

[DanOSTL]

I’ll be snagging one of these. Thanks for the heads up!

 

[UCChris]

Gotta wonder why so cheap. Even if used its a great price. Makes me cry knowing what I paid for mine. I have a 15 and a 17, great bottles. Reg is a beast to remove.

Ninja makes a HPA 3k output version (2900 actually).labeled as an x or custom. They work great.
Hajimoto sells the v2 and flex at custom setpoints for up to 2400 as i recall and with the right threads.

New England Airgun also has a few ninja reg’s on their site.

Fyi, found this out the hard way, some Ninja regs use a ball/spring valve, some adapter blocks may not depress it far enough and has to be removed.

Beats me why they're so cheap. All three of mine from ANSGear appear to be new. I saw no signs of use and all had the factory grease on the internals. All mine came with hydro dates of 11/2021 though.

One more thing...extrapolating from your photo, it looks like the shaft is over 0.8" long which means it will take a stack of 27 of the above Bellevilles (0.030" high) to fill it up. As absurd as that sounds, it is actually favorable in terms of setpoint repeatability.

The factory red pressure spring measures .86", from the wide part of the piston to the closest edge of the small oring on the piston shaft is .81"

I presume we want the Belleville stack to match the length of the factory spring, give or take? That would be 28 of the .03" tall Bellevilles and two .01" shims.

My bottle Prod shoots 13 fpe (13.43 at 661) on that 1450 psi Ninja reg that you did up for my QB. When I screwed in the carbon bottle, it dropped to 9 fpe with the same pellet, so I would assume around the industry standard 850 psi. I know pressure/fpe is not a linear relationship, but I doubt I would see a 30% energy reduction if the reg was near the 1000-1200 psi they quote with their high pressure kit.

As an aside, I tried to get an answer from First Strike on the MSWP of the bonnet by asking about a scenario where someone might screw up and put one of the 7.5k burst disks in place of the 1.8k and the regulator fails at the same time. For liability reasons they declined to comment on any pressure to the bonnet over 1.8k. So my quest to find any regulator we know is safe to use as an unregulated bottle continues.

Edit: Saw this little tidbit about stacking these suckers on the McMaster website. I don't know what sort of wizard math you use to determine the best orientation to start testing output pressures, but it sounds exceptionally painful. Especially at 3:25 am.

It should be fairly straightforward to calculate stacks such as (((( or ()() but stuff like )(())( requires order of operations or something with the nested pairs being like .05" tall or something? .03" high with the nested washer adding .02"? I've confused myself at this point.

Zzzzzzzz it's bedtime.

 

[UCChris]

Going to be picking up Bellevilles from McMaster today. I've got a spare 1.8k burst disk so I have some room to fiddle with the output without worrying about going too high. I don't have a way to test output pressure though, so it's going to be a lot of testing with my bottled Prod that I know does 660 fps with a 1450 psi regulator.

My understanding is that if the Belleville stack is too short or weak enough that it compresses completely, the regulator will fail and we'll lose a burst disk.

I'm a little uncertain on the other end though. If the stack is too long or too stiff, I would assume the regulator wouldn't output anything as the setpoint is too high. Then I would presume that I would need to either gently unscrew the 7.5k disc, gauge, or regulator itself to carefully drain the bottle?

 

[nervoustrig]

My understanding is that if the Belleville stack is too short or weak enough that it compresses completely, the regulator will fail and we'll lose a burst disk.

The reverse...if the stack is too tall or too strong, the regulator's valve seat will stay open regardless of the pressure and the burst disk will fail.

If it's too short or too weak, the output pressure will just be very low or may pass almost no air whatsoever.

[edit]
Is there anything about the Prod and its modifications that necessitates you limiting the pressure to no more than ~1.8k? In OEM form it is a 3k fill platform so you can perhaps install a 5k burst disk while you tune the output pressure, to avoid inadvertently popping a 1.8k burst disk.

 

[UCChris]

The reverse...if the stack is too tall or too strong, the regulator's valve seat will stay open regardless of the pressure and the burst disk will fail.

If it's too short or too weak, the output pressure will just be very low or may pass almost no air whatsoever.

[edit]
Is there anything about the Prod and its modifications that necessitates you limiting the pressure to no more than ~1.8k? In OEM form it is a 3k fill platform so you can perhaps install a 5k burst disk while you tune the output pressure, to avoid inadvertently popping a 1.8k burst disk.

Thanks for clearing that up. That's what I get for posting on AGN moments after waking up.

The Prod has a Cothran tube and Gauntlet tank block that is secured with four screws. As long as the paintball ASA threads and the bonnet can handle it, there's nothing that would keep the gun from handling 3k. The struggle here is that the tuning of the Prod is gonna be kinda weird since it's got a tiny 7-ish CC plenum. I could be dead wrong, but I'm worried that I might see a situation where the reg could be set to say 2300 psi and it's shooting similar to the speed of the reg set at 1800 psi since both shots are dumping the plenum and the pellet is gone out of the short barrel early in the shot cycle.

I was thinking about starting low and slowly increasing until a 1.8k disc goes, then I know I need to back off just a hair. Am I off base?

Any idea what stack you would start with?

 

[nervoustrig]

I'm worried that I might see a situation where the reg could be set to say 2300 psi and it's shooting similar to the speed of the reg set at 1800 psi since both shots are dumping the plenum and the pellet is gone out of the short barrel early in the shot cycle.

That's not quite how it works. Approach it like this...each time you reconfigure the spring stack for a new (unknown) pressure, start by adjusting the hammer strike to find the new velocity plateau. Provided you can, leave it adjusted to the plateau and shoot over the chronograph until you see the velocity begin to tail off. Whatever the bottle pressure is at that point* is a pretty accurate representation of the regulator's setpoint.

Leaving it on the plateau is preferable for this purpose because if you instead adjust it down to the knee per standard practice, the velocity won't tail off until the pressure has fallen somewhat below the actual setpoint. What is an advantage for normal shooting is a disadvantage for the task at hand.

* The piddly compact gauges on bottles aren't much good for this purpose. Their accuracy is poor and resolution too coarse. If you have a hand pump with a trustworthy gauge, pump up until the bottle's check valve open and that's your regulator's setpoint.

 

[nervoustrig]

Any idea what stack you would start with?

Just a simple series stack that fills up the piston down to the O-ring. My guess is that will end up producing a low-ish setpoint that will then need shimming. But that's just a guess...I have no idea how much travel the piston has to undergo to reach the seat.

Tracking says my bottle is supposed to be delivered later today and the Bellevilles already arrived. If I can make time this weekend, I'll give it a shot and report back.

 

[UCChris]

Thank you for the guidance! Can't believe I didn't remember you can use the plateau to check reg pressure, I really am rusty at this stuff. Also, I realized that I've got a paintball remote whip and I can use my Diana Bandit cylinder as a pressure gauge, so I'll be able to check output pressure. I'll calibrate the gauge with my known accurate gauge on my fill tank.

I'll probably start with 28 Bellevilles with no nested pairs - ()()()()()()...etc and two .01" shims.

 

[nervoustrig]

Alright I've been experimenting with it and recording notes. The tl;dr is I have mine adjusted to 1300psi using the Bellevilles mentioned earlier in the thread.

PARTS USED

• Belleville spring washers - McMaster #9712K59 (0.19 ID 0.375 OD, 0.020 thick, 0.030 relaxed height, 110lbs flat rating).
• flat washers - McMaster #92141A009, opened up ID per picture and instructions below.
• shims - 0.004" thick punched out from typical aluminum soda can, picture and instructions below.

PRESSURE ADJUSTMENT TRIALS

• 24x Bellevilles + 4x flat washers + 0x shims -> 1050psi
  ^ number needed to fill up piston to the O-ring
• 16x Bellevilles + 10x flat washers + 0x shims -> 1500psi and climbing (stopped pumping)
• 19x Bellevilles + 7x flat washers + 0x shims -> 1150psi
• 19x Bellevilles + 9x flat washers + 0x shims -> 1500psi and climbing (stopped pumping)
• 20x Bellevilles + 8x flat washers + 0x shims -> 1200psi
• 20x Bellevilles + 8x flat washers + 3x shims -> 1550psi and climbing (stopped pumping)
• 20x Bellevilles + 8x flat washers + 1x shim -> 1300psi

Bear in mind every regulator and pack of Bellevilles will be a little different so don't treat the above as a recipe. Only trial and error will give you a particular setpoint.

SEALS

1. bottom of piston: M1x3 polyurethane, unsure of durometer...best guess is 70
2. top of piston: -010 polyurethane 70 durometer
3. seat (end of piston): 3mm plastic ball (black...Torlon?)
4. bonnet cap: -012 Buna-N 70
5. check valve (pin in bonnet): M1.5x2, polyurethane (didn't remove to check durometer)

OTHER THOUGHTS AND OBSERVATIONS

1. The seat is a separate part, not machined directly into the reg body like a Ninja regulator. That means it can probably be threaded in and out to adjust the setpoint, however I have not tried to do that yet.
2. I am seeing virtually no pressure creep. It comes up to the setpoint promptly and stops. Good sign for a new regulator before any meaningful break-in period.
3. The indexing bonnet with magnetic collar is a clever feature.
4. Removing reg from tank required no heat (no threadlocker). It was tight though. Clamped bonnet in vise, applied a turn of electrical tape around the tank (for grip) and used a rubber strap wrench to break it free.
5. Regulator is compact...adds very little length to the bottle compared to typical paintball regs.
6. Yay for math. Predicted the Bellevilles would be good for ~1400psi. Managed 1300psi in practice.

WEIGHT
13.18oz vs 18.43oz for Ninja 13ci aluminum bottle (standard reg, not Pro v2)

TANK DIAMETER
1.985" diameter for carbon fiber tank vs 1.965" for aluminum Ninja tank (maximum measurements...each has some small variation along its length)

Initial disassembly:

Spacers made from #8 washers.
Originals on left, altered on right. Used conical carbide burr to open up ID to 0.195", then cleaned up rough finish with diamond abrasive bit. Finished by flattening both surfaces against sandpaper:

Shims made from aluminum soda can.
OD made with 3/8" hollow punch. ID made with 5mm hollow punch. Sandwiched between flat washers to prevent wear.

Pressure set to 1300psi:

 

[UCChris]

Awesome writeup! Are you stacking Bellevilles, then washers and shims?

()()()()()()()()()()|||||||||

Or are you putting washers between Bellevilles? Does it matter?

 

[nervoustrig]

I like to place a flat washer at each end of the stack just to keep the Belleville rims off the relatively softer materials of the piston and reg body. But in terms of the spring rate and the resulting setpoint, the locations of the washers is unimportant. Put them wherever is convenient.

 

[UCChris]

Picking up my washers and stuff today. McMaster wants $35 for a 5mm punch that does aluminum. They have a $12 punch that they says does leather/rubber, that should be good enough for a thin aluminum can right?

 

[nervoustrig]

Yeah I think so...the punches I have are not advertised as being for aluminum, brass, etc. but a soda can is so thin that they work adequately.

 

[UCChris]

Okay, the punch works for aluminum, so that's figured out. How are you holding the washers to drill out the ID? I'm trying to run a 3/16" drill bit through the center, since I don't have a conical carbide bit. I'm trying to use light pressure, high drill speed, and some oil to cut very gently, but I keep having my holding methods slip, or grab so tight the washer bends. I tried to use a little clamp as well, but distance from the ID to the OD is small enough it's having a hard time grabbing with enough room to drill.

Since I was struggling with the washers, I decided to do a 28 washer stack in series starting and ending with one facing "outwards": )()()()()()()()()()()()()()( That got around 200-300 psi, according to the gauge. I then stacked some washers going with a few nested washers. Using 29 bellevilles, from input side to output: ))()()()()()()()()()()()()()((( This made little to no difference, maybe an additional 50-100 psi? It's clear that a large stack of bellevilles runs out of space on the piston body before being strong enough for a decent reg setpoint.

@nervoustrig In your testing notes when the reg went to 1500+ and you stopped pumping, was that because you didn't want to blow a burst disk or did you figure the stack had flattened and was wide open?

 

[nervoustrig]

How are you holding the washers to drill out the ID?

You're right, using a twist drill bit to enlarge the ID is almost sure to fail. That's why I used the conical carbide burr to do it...it doesn't grab the washer anywhere near to the same extent, so I can just hold the washer by pinching it horizontally between the jaws of my vise (metalworking vise with aluminum angle in the jaws so it has a little give to it).

Potential alternatives would include most any cutter that doesn't self-feed the way a twist drill does. A typical step bit is one example since the cutting edge runs parallel to the axis of the bit, rather than spiraled. Or maybe you have a Dremel kit with a conical stone...not sure if that would work or just clog the stone straight away. Last resort: a small round file. Maybe then use a conical stone to true up the hole.

Otherwise if you have a set of numbered drill bits, you might be able to get that to work by stepping through them one by one. Taking just 3 to 5 thousandths at a time isn't as prone to snagging the washer and spinning it free.

It's clear that a large stack of bellevilles runs out of space on the piston body before being strong enough for a decent reg setpoint.

That was my thinking as well. Such a large number of Bellevilles produces a large amount of travel when we are trying to operate fairly close to their maximum load. So to get that to work, we would need to extend the stack on past the small O-ring so reassembling it would apply a substantial amount of preload (i.e. "use up" some of the excessive travel).

That just seemed too messy and unconventional so I switched tactics and swapped out some of the Bellevilles to flat washers to reduce the total available travel.

In your testing notes when the reg went to 1500+ and you stopped pumping, was that because you didn't want to blow a burst disk or did you figure the stack had flattened and was wide open?

A little of both. I didn't want to blow the burst disk and my calculations said the Bellevilles would be pressed flat somewhere before 1500psi.

 

[UCChris]

You're right, using a twist drill bit to enlarge the ID is almost sure to fail. That's why I used the conical carbide burr to do it...it doesn't grab the washer anywhere near to the same extent, so I can just hold the washer by pinching it horizontally between the jaws of my vise (metalworking vise with aluminum angle in the jaws so it has a little give to it).

Potential alternatives would include most any cutter that doesn't self-feed the way a twist drill does. A typical step bit is one example since the cutting edge runs parallel to the axis of the bit, rather than spiraled. Or maybe you have a Dremel kit with a conical stone...not sure if that would work or just clog the stone straight away. Last resort: a small round file. Maybe then use a conical stone to true up the hole.

Otherwise if you have a set of numbered drill bits, you might be able to get that to work by stepping through them one by one. Taking just 3 to 5 thousandths at a time isn't as prone to snagging the washer and spinning it free.


That was my thinking as well. Such a large number of Bellevilles produces a large amount of travel when we are trying to operate fairly close to their maximum load. So to get that to work, we would need to extend the stack on past the small O-ring so reassembling it would apply a substantial amount of preload (i.e. "use up" some of the excessive travel).

That just seemed too messy and unconventional so I switched tactics and swapped out some of the Bellevilles to flat washers to reduce the total available travel.


A little of both. I didn't want to blow the burst disk and my calculations said the Bellevilles would be pressed flat somewhere before 1500psi.

As always, thank you for your knowledge and for sharing it so freely. I'll pick up a carbide bit and go from there.

I might try testing some stacks with preload, since I'd love to see if these can be pushed to 1600-1700 or if it'll require too long of a stack. Of course we'll see if the burst disks are as unreliable as the Ninja style ones.