Regulators: A project/idea

[Thorpydo]

Hey,

I'm sure most of us here know how a regulator works; The components used and how they function with each other. However, I, and I would guess most, don't know how far everything moves and when it does. ie: does the valve open .002 or is .01? Does it open more when railing on the trigger? Does it bounce open and closed?

I guess someone could tell me these things but I know most of the rumors and BS that gos around on a more basic level, so I don't know how much I would believe it.

I'd like to build a regulator to take a look at all these things. I have all the gutted internals of my HPR on my timmy. What would be envolved would be basically making a body. I've got a mini-lathe/drill press, so it shouldn't be too hard. I'll have to buy a bit or two and a reamer. I was thinking of using polycarbonate, also known as lexan, for the body. I was planning on having a quater-inch wall on either side of the largest hole. Do you think this be strong enough?

I think that when I start drilling into the polycarbonate its going to turn white, but polishing it will make it clear again. What should I polish with? A 'bunny ears' squeegie and some metal polish? Is there a better type?

I drew this up tonight. I havn't thought about it much and there may be some errors to work out. You'll notice that the input and output holes are similar to a cocker's LPR. It's easier and doesn't require the machining that a inlinde reg does. Normally, the reg has one more piece that I took out. It is what would normally keep the stem and O-ring of the valve in place. Taking it out gave me more room on the bottom for the output hole (Again, not normally in inline regs). But now I don't know that I have a large enough passage for the air when the valve opens (Look at the input hole and the stem of the valve).

Lastly... The bolts. I'm tired and didn't make them look purty. The big one is 1-8 and the small one is either a 10-32 or something bigger.

Lastest... I've got a digital camcorder that when done, can record some tests.

And one of the reasons for doing this, besides curiosty(sp), is that I've got a idea on how to simplify things but don't know how it will perform.. So I'll actually be making 2 regs.

Thoughts? And answers to questions :)
Thanks!

[Thorpydo]

And the other.. It's a cutaway view.

[Natural Newbie]

That should be plenty strong. As for the polish I have this stuff at home specially for plastics, I will see what it is and let you know. Looks good, what program did you draw those up in?

[Thorpydo]

Ok, great, thanks!

I use pro/engineer. It's a great program and I love it.

[nerobro]

Regs are progressive devices. the only way you'd get reg seat bounce is in individual cases wehre the seat doesn't sit right. and the moment it started to bounce the output side would go over pressure and seal it ;-)

As the pressure on the output side rises the piston moves and closes the reg seat. it's a very progressive thing. Terminating when the seat has enough pressure on it to seal.

the design you're making is only a single case scenario. there are other regulator designs out there as well. the design you're copying is one of the more common designs. Basicly the same as you'll find in a classic mag, unireg, ans gen-x, boblong's regs, the vigilante, messiah, apoc, conquest, and I could keep going.

now the other kind are the style like you'll find in govinair, crossfire, WGP, WDP, and sidewinder regs. That's

the interesting ones to watch are the RT and maybe the maxflow.

Every reg but the retrovalve all behaves the same way. the valve is wide open untill the pressure comes up to close it. It will close slowly and progressively untill the reg piston ballances out and the reg seat is closed.

[Natural Newbie]

Well said nerobro. Thorpydo, that polish is called Meguires Scratch-X. It's a very fine polish to be used on automotive clear coats and plastics, it's great stuff. One thing I was thinking about. For the valve pin, the o-rings seat is a drill point right now. I don't know how well it will seal on that. You could make one like that, then make another one using an end mill of the same size. Keep us updated!:)

[Thorpydo]

Yeah, I'm not sure. I know it will seat, as we've got something similar on the marker were building, but that o-ring is static and this is a bit different.

I don't have a mill but... There wouldn't be any problems with just sticking a end mill on my press would their? It's a big ol' Grizzly.

[Crimson_Turkey]

Thorpydo kicks butt.

[nerobro]

"Thorpydo: Why don't manufactors increase the diameter of the pin valve? It would seem like that would increase flow without effecting consistancy"

An excerpt from our AIM conversation after talking about how much lift the unireg design acutally gets.

The larger the pin seal aera is, the more the regs output is affected by the input. That's what is refered to a regulators pressure ratio. IF I have my numbers right. the unireg, due to it's small reg piston is a 25:1 reg. the stab is on the order of 50:1. Now on conventional regs, like the one you want to put togother as you increse the input pressure the output pressure will drop. Because air pressure on the pin will effectivelly take away some spring tension.

Now you ask why companys don't go with larger reg pin dia's. Well... they do. if you've taken apart a WGP reg, that whole tube down the middle is the dia of it's reg seat. Now tha'ts the design I call ballenced piston.. due to the fact the whole moving body in the reg is just a single large piston with a tube attached to it. And if it says anything, to achieve a really high flow reg, AKA copied the design. Now keep in mind, the design can also be screwed up... take a quick look at the WDP inline regs... 10 secconds to recharge.... course that culd just be bad springing.. and have you ever looked at the gas path through that reg? *winces*

Long story short, regs are a whole bunch of tradeoffs. but their behaviour is very predictable. Make the reg pin to big, and you see problems with output pressure. Make it to small, you see flow issues. Put the reg piston in the way of the flow coming out of the pin, and you'll never achieve a lot of lift... (like the unireg...) Course now we're getting into reg design....

if you take a look at the output graph of a reg, you'll see how progressive they are, and you can see how the pin slowly closes as the pressure climbs.

[Cristobal]

Sounds like a fun project!

A couple thoughts:

1.) DON'T put an end-mill in your drill-chuck. The end-mill is designed to go in a collet that will wrap completely around the tool, holding it much firmer than the three jaws in your chuck can. Putting an end-mill in a chuck is a good way to break/shatter it... not that I haven't seen it done (sometimes in the drill chuck on the tail-stock of a lathe) but I can't recommend it unless you really know what you're doing.

2.) Also, if you want to make the reg o-ring seat against a flat rather than angled base (like you'd get by just drilling the hole) you probably wouldn't want to use an endmill anyway. The endmill will angle down towards the sides, so it won't get you a square base either (just the reverse of what you had with the drill). What you
really want would be a counter-bore tool. Since you're running a hole all the way through for the air passage,
you can use that as your pilot hole, drill down most of the way a drill bit at the larger diameter, and then
use the counter-bore of the same diameter to square off the bottom of the hole. The counter-bore is also designed to work fine in a drill chuck

3.) Use a little Windex (or the like) as a cutting fluid, and play around a little with your rpm and feed rate and you should be able to make nice clean cuts in the lexan that you can see right through -- that should cut down your polishing job.

[Thorpydo]

Thanks for the adivice.

Makes sense with the endmill, but arn't there endmills with a flat bottom face? But then how could it cut down? Well, I don't 'really know what I'm doing', so I wont try it.

I think I'm going to order some taps and such from J&L soon, so I'll make sure to look at counterbores. I see what your saying with the pilot hole.

Windex? Like the stuff people clean windows with? I've got some all-purpose cutting fluid. I don't think that includes plastics though. I havn't been using anything when I'm turning ertylte.

Now that I think about it, I had a physics project a while back and I made the wheels out of what I'm pretty sure was polycarbonate. It was the made from the window we had off an old sailboat. I did't get a clear cut, but wasn't trying to (due next day). I'm getting off topic.. I know

[Natural Newbie]

Cristobal is right about everything! :). Endmmills cut a flat surface when they are swept across the surface. But the end of an endmill is actually concave .

[Cristobal]

Not all can endmills can make a plunge cut straight down into material like a drill; to do that you have to have a center-cutting endmill where the bottom edges of the flutes meet together at the center of the bottom face.

I've been looking all around for a picture of the difference between a centercutting mill and a non-centercutting mill. This is the best I've found:

http://prl.stanford.edu/documents/html/gnrlmill.htm

EDIT: Yes, Windex (the kind you use on windows ) For clear plastics it makes a nice cutting fluid... just be sure to wipe up any excess or spray afterwards, as it will tend to cause your vice and/or tools to rust/oxidize faster if you let it just sit on stuff.

[Thorpydo]

Pretty interesting... Learned quite a few things

Thanks

[AGD]

If your thinking that a clear reg will allow you to video the movements and study the system you are probably in for a dissapointment. The parts only move a few thousandths of an inch very quickly. I highly doubt you will see much in a video. If you want to experiment, put a small shaft down through the reg nut hole on the back of the mag. Shoot it and look to see if you notice the shaft move. The reg piston is opening and closing and moving the rod with it. If you can't video that you have no chance looking through plexiglass.

AGD