Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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I am in the process of building a one inch piston valve.
Once done, I'll mount the half inch barrel, and the 2 inch chamber to it.
I want to see how much difference, if any, I will get with a larger piston valve on essentially the same airgun as the half inch airgun I presented at the end of the last thread.
I'll build the valve first. Once it is working then I'll decide on the barrel, chamber, etc.
An option I may go with, instead of the 2 inch chamber, is a 1-1/4" chamber instead.
If I go with the smaller chamber, it will be because of looks, as well as a better possibility to get the entire airgun built to look more like a 'real' gun.
Two builds I am considering for the future are 1. A "coaxial" air gun. Where the piston and barrel are housed -inside- the chamber...
And 2. Possibly an attempt to try to make a full size replica of something like the guns in "District 9"... But as working airguns...
Right now, though, I am still very much a newby to this. I have a lot to try, and to learn, before I can make anything like a working airgun replica of something else.
I have a lot of stuff running through my head. Ideas that I'd like to try. Like heating PVC to malleable, leather-like states, to build things such as stocks, recievers, etc. Non-pressurized parts. And working with bondo, brass, aluminum and other ways to make these things look 'pimped out'. LOL
Cost will be, as always, the major limiting factor. But then, that's part of why I want to do things the way I want to. To try to keep costs down. Just as working with that half inch valve until I got it to work without having to include the sprinkler valve.
I do think that unless I can come up with a faster flowing homemade pilot valve, of my own, valves in the range of 1-1/4" and larger are going to have to be piloted by sprinkler valves. (Which are in turn piloted by blowguns.)
One idea I have for a pilot, is an ordinary pressure relief valve. The kind used on compressors. They 'pop-off' at a certain pressure, in case the compressor regulator switch goes kerplooey, and the compressor just keeps pumping away. Keeps it from blowing up. LOL
If that doesn't flow fast enough, I will probably try a few ideas I have with fittings, springs, bolts, and o-rings.
~~~
So much to do, so little resources.
Including volition.
But then, keeping the volition stoked, is part and parcel to my reasoning for doing all this...
~~~
Next, some pics.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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I'll try to keep better track of the progress on this one.
More pictures. Maybe better explanations. (If you have any questions, feel free to ask.)
~~~
Like I said, I am going to build the valve first.
Once it is actually working, then I'll tend to the rest of the build.
From left to right...
The barrel stub.
A 1" to 3/4" reducer fitting.
1" tee.
1" pipe that will become the piston chamber.
3/4" pipe that will become piston.
Wood dowel. This has been wrapped with tape, to make a very snug fit inside the 3/4" pipe. It will be epoxied into the pipe.
Then the outside of the pipe will be reduced in size until it fits tightly within the 1" pipe section.
The wood dowel is longer than the 3/4" piece of pipe, because the dowel is to stick out the front of the piston, and have the barrel sealing face affixed to it.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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Second pic.
The parts essentially the way they will look, when assembled.
The dowel is on the wrong side of the 'piston', but you get the idea.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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This is the 1" to 3/4" reducer.
This will be inserted into the 1" tee, and the barrel stub will be pushed through it, into the position needed, to make a barrel seal with the piston.
The fitting had a 'stop' in the end of it, to keep the 3/4" pipe from going all the way through.
Of course, I WANT the 3/4" pipe to go all the way through. LOL
So, I have to hog out that 'stop' in the end.
This pic shows one fitting with the stop still there, and one fitting already hogged out, to allow the pipe to go all the way through.
That isn't as easy as it may seem.
You have to be patient and persistant, to get it hogged out just enough, but not too much. And to keep it from becoming out of round.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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Next, a pic of the 'barrel stub' sticking into the tee.
Most people run the barrel to the center of the tee.
I don't like to go that far.
I prefer a compromise distance. One that can still be reached without over-centering the piston, and risking it jamming... But still far enough back, to allow more free air flow, once the piston unseals from the barrel.
In the pic, you can see the seam that is the center of the tee.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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In this pic you can see that the wooden dowel has been epoxied into the 3/4" pipe.
It is sitting beside the 1" pipe that it will have to be made to fit inside of.
It almost fits inside, already. It shouldn't take much 'lathe' work on the drill press, to get it to the point where it is a tight fit.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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And this is the last pic for the night.
The piston is laying beside the rest of the 'valve', in the position it should be sitting, once the valve is put together.
I should be getting that piece worked on pretty soon.
I have some thngs to take care of first, due to the recent snowfall.
I'll be back to show progress, whenever there IS any...
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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I've taken a bit of a different tact with this piston.
Instead of building up on something that was too small, I will use my benchtop drill press as a sort of vertical lathe. I'll use it to reduce the OD of the 3/4" pipe which is the piston, until it slides into the one inch pipe.
To do this, I'll drill through and insert a bolt.
Then chuck the bolt into the drill press. And use sandpaper and files on the piston, until it is the right diameter.
Here are the materials. The piston, the bolt, nuts, and bearing.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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To make the bearing work, I have to reduce the size of the head of the carriage bolt.
I chuck that into the drill press, and then use the file, while the drill press is running.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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Now I can install the bolt into the piston.
Chuck that into the drill press.
Clamp the bearing in the vise.
Run the drill press down just enough to set the turned down head of the bolt into the bearing.
This will prevent wobble, which would cause the piston to end up out of round.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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This is the finished piston. (Well, without the washers and rubber seal.)
You can see that it slides all the way through the pipe that will become the piston bore.
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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Here is the piston started into it's bore.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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The valve.
Piston in the open position.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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Piston closed.
The seal here is just a washer from a plumbing repair kit.
I am afraid it is not a large enough diameter.
I may have to cut a better seal for it out of some of the red rubber you can get in small sheets, at Lowes.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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Well, as usual, life ineterfered while I was making plans to continue this thread.
I didn't get all the detailed pics I wanted. I've barely had time to get some small part of it done, every day. No time for pics.
I did get this pic. It shows the valve pretty much together, and labels the parts used. But no chamber or barrel, yet.
BTW: The grey pipe you see here, is actually rated to a higher pressure than standard sch40 PVC.
1" pipe comparison is: white sch40 PVC = 460PSI
The grey stuff = 640PSI
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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Here is a pic of the pretty much finished airgun.
It's a bit bigger than a pump shotgun.
You can see that I took the grey 1" pipe and elbow off of it.
I decided to try to keep the chamber as close to the barrel as possible.
You also see a blue-handled ball valve on the barrel. That is a breech-loading device.
It has a hole cut in the top side. When you "close" the ball valve, the hole in the ball, is exposed.
Pack a piece of steel shot meant for a slingshot, into some toidy paper, then pack the whole thing into the ball valve.
Then "Open" the ball valve, and yer ready to shoot. (Opening the valve, lines the hole in the ball, up with the barrel. Just as opening it when connected to plumbing, lets the water through.)
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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It will likely stay this way until I have a chance to test it.
I'll put a bunch of steel shots through it.
I'll also try darts. And at some point I'll probably make a more conventional looking breech, so that I can drop darts in, instead of having to muzzle-load them.
Sometime this winter, I'll try to make a metal airgun.
You can take a metal one to much higher pressures.
To get those pressures, I'll probably have to convert a refigerator compressor over, to air compressor duty.
They may be slow getting there, but some people have gotten them to pressures in excess of 1000 pounds.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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Post deleted by Luka
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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The above airgun will put a 3/8" steel shot, halfway through an old, very tough, and soaked through and through, piece of 3/4" plywood.
A double 'a' battery, wrapped in tape to make a snug fit in the barrel, will do the same damage.
I am going to have to build a different kind of breech loader for the nail darts, because they get damaged when you try to muzzle load them. They have to be stuffed backward down the barrel.)
I tried somehting a bit different, after the first few steel shot loads. I made sabots out of short pieces of wooden dowel, wrapped in tape for a very snug fit.
Muzzle loaded one of those. Then a steel shot, wrapped in enough toidy paper, to keep the shot from just rolling around.
This shot went deeper into the plywood, and left the hole stuffed with toidy paper.
The wooden sabot hit about an inch away, and caused as much damage as the original steel shot tests.
So, I'm going to look around for something to use as a barrel, that the steel shot will be a very snug fit in.
And in the meantime, I am making a longer 1/2" barrel, a 3/4" barrel, and a 1" barrel.
The common wisdom, when I asked, was that apparently a longer, -or- a larger barrel, will deliver more damage to the plywood, with the same steel shot. And at the same pressure. (With the steel shot properly sabboted, of course.)
I'll glue the barrels up tonight. Maybe have time to test them tomorrow.
I have been busy the past couple days, helping the neighbor with actual plumbing. LOL Putting in his water tank, pressure pump, etc. He may want me to help him on it again tomorrow and/or the next day.
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The true measure of a man is how he treats someone who can do him absolutely no good. ~Samuel Johnson
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Luka
Reged: Apr 25 2002
Posts: 1387
Loc: The great NorthWet
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What I was hoping for with this one inch valve, is "power", but keeping it as small a size as I can.
My goal was to get a 3/8" steel shot through a tough old piece of 3/4" plywood that is soaked through and through. (Being saoked like that, makes it more difficult to get an object to penetrate. And it is a really tough piece of plywood, as well. Not like the newer stuff.) From about 35 feet away.
Well, here is the pic of 'the damage', using a half inch barrel.
The "short barrel" (2 feet) was used for the left shot, and for the AA battery.
The steel shot only made it about halfway through the plywood. The AA battery went a tiny bit further, but caused more damage.
The "long barrel" (3 feet) was used for the top shot. That one went a bit deeper, but not much.
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