New data/info for my regulator.
Ok, this concerns the spring-washers.
Firstly I decided a firing pressure of 2000psi was adequate for each shot, from a volume of approx 19 cubic CM. If that is in the ball-park…
The compressed air has to flow from the main bottle into the regulator chamber. When the pressure in the regulator chamber reaches 2000psi the flow from the main bottle needs to be shut off. I devised a design where this was to be done by the pressure in the reg-chamber acting upon a piston in a shaft that would force a block across the inflow from the main bottle.
The main consideration in this was a spring that would fully compress and shut the gate at 2000psi. All of this needs to fit in a tube no greater than 16mm diameter (the space in the neck of the bottle).
Given that, the valve inside the reg-chamber needs to be no bigger than 10mm diameter.
A coil-spring of that OD would need to be approx 18″ long to compress and give sufficient travel to a shut-off pin at 2000psi. Not viable at all.
So, spring-washers.
One spring-washer at 10mm OD x 5mm ID x 0.5mm thick requires a force of 325N to deflect 75% (the max recommended deflection for this washer). 2000psi is 1100N. Three washers = 975N, a bit too low, so have to go up one to x4 washers = 1300N (a bit more than 2000psi, but close enough).
To get the neccesary travel, at least 2mm at 75% deflection, 56 washers are required, mounted in 14 series of 4 (alternate facing). This causes all the washers to deflect at only the force needed for four.
Still with me? 😯 😆
Free space required for 56 washers: 31.5mm
At 15% pre-load (required): 30.94mm
At 75% deflection (recommended max): 28.84mm
Add 3mm for the piston and that’s a total valve-area length of approx 35mm inside a reg-chamber tube measuring approx 25cm in length (at 16mm OD).
If the volume lost to the valve area (approx 0.75cm radius x 3.5cm length = approx 6 cubic cm) is deducted from the total reg-chamber area (0.75 radius cm x 25cm length = approx 19 cubic cm) it’ll leave approx 13 cubic cm at 2000+psi. Enough for a good shot?
Anyway, that’s where I’m at right now. Comments welcomed as always. 🙂
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What supports the barrel out the arse-end of the chuck? All that weight/length supported right at one end in the jaws…ooer! 😆
The barrels long, but your only machining about 3 inches.. so you have most of the barrel passing through the headstock so the area you’ll be cutting is close to the chuck.
I do not have it yet. When it come I will take some pics.
Ah ha! 😀 Let’s have a look at it then.
I just got a steady rest of ebay with roller bearings for ~ $115.
Turning a barrel for the Talon. 😯
Well, therein lays the problem. The barrel is a long thing, and I’m a bit leery of the shoddy looking centre-supports on my lathe (I’m talking about the fixed and travelling steadies). Rough isn’t the word. I’m going to guess/assume it’s possible to get steadies with roller-bearings? Because spinning work between pointy brass things seems a bit dodgy to me.
Yeah, it easy alright. And you know what one of the easiest thing to do is?
Turning a barrel for the Talon. 😯
Or, to put it another way, I’ll soon be swinging off the knobs and dials like a fez-wearing organ-grinder’s monkey, lathing to a rendition of the Banjo Duel played by a psychotic guitarist on crystal-meth.
I’m sorry, but I’m not entertaining this mythical difficulty jazz that’s going on (no offence 😆 ). I don’t know why people do it, unless it’s because they themselves have found it hard? I found nothing about the actual physical process difficult when I did it many years ago, though I do remember the math was dead boring (working out feed-rates and stuff).
I must admit though, I’m a bit of a winger. I’ll take twice as long, and do a job by hand/feel/eye, but still get it done to spec. So what, I’m not working for anyone but myself.
I also remember feeding the tool into the work as hard and as fast as I could, just to see what would happen. I guess I found the limit that way, which was hugely educational. I do know I have a feel/affinity for cutting metal, a memory that has stayed with me all these years. You can hear and feel when it’s not right. So I’ll bust/burn a few tools and pieces of work maybe, but I’ll soon be back up to speed.
But mainly it’s supposed to be fun, right? This is a hobby, not a job, though undoubtedly it’d be nice to be able to sell bits and pieces one has made. A bonus, not the object of the exercise. My regulator project is for pleasure, the pleasure of making something that has a discrete purpose for which I feel a need (a better functioning rifle). 😀
I’ll also be making a Blodnob-type valve, which I WILL be offering for sale within the UK (the nazi’s running this country can go fuck themselves).
It’s a lot harder when you actually start to cut. And setting your lathe up properly takes a good bit of time.
My cutters and suds should be arriving tomorrow, and I’ve found a nice length of steel which I intend to use to make a one-piece tophat & stem. Will that do? 😆
Turning a barrel is many times easier then turning precision parts for a regulator.
Even a Yellow Ninja can do it.
I can turn a barrel, which means its easy. Give it go… for me… please
The construction of the regulator will actually be pretty simple, there’s nothing complex in it’s design. A few shafts drilled, a few threads cut (which will be easily doable with a tap & die set). Whether or not the entire ensemble will have the desired effect is another matter, but it’s worth a try and it’s certainly within my means and meagre abilities.
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eBay link?