Pneumatic powered bullet sizer? Anyone made one?

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Analogkid

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I am a machinist by trade and would like to build something like this to save my shoulders and elbows, they are already in bad enough shape as it is. My specialty is not pneumatics and am seeking advice from someone that is. Maybe a few folks here are well versed in the subject.

I see a few of these on youtube and some of them look pretty dangerous but one has caught my attention because of the delivery tube that keeps your free hand away from the push ram. I'd probably go a little further and just enclose the area with plexiglass and only have the delivery tube accessible.

You know to take the Idiot (me) out of the equation and to keep from getting a cool nickname like stumpy..nubs ect..

None of the folks that have youtube video's are active anymore and do not reply and like most never put any specs in the video for the items used.

I assume this would have to be a double acting Cylinder? What actuator would need to be used?
Here's the specific air ram setup I would like to build. I have a few lee challenger presses I would like to put to use.

 
I am not a pneumatic expert but I did convert a wood mortising machine to pneumatic power down and up feed.
A few things I learned:

1) How much force do you need to push the bullet through the sizing die? I don't know how to measure this??? Maybe put a bathroom scale on top of the press ram and put your weight on the scale until the bullet is pushed though the die.. reading the highest weight the scale registers. Lets say it takes ~110lbs of force to push the bullet through the die???

2) What size pneumatic cylinder do you need? The amount of force a cylinder will put out is equal to the surface area of the piston face X the PSI of your air supply. So lets start with a cylinder that is 1.6" dia. (1/2 X 1.6") ^ 2 x 3.14 = 2 square inches of piston face surface area. At 55psi x 2sq-in = 110lbs of force. A good starting point!

3) I would recommend a power down stroke with a spring return. It is a lot more complex to power the down stroke and power the up stroke (with a mortiser you have to push the square chisel down through the wood then pull the chisel out of the wood and overcome the large amount of friction between the chisel and the wood. I went powered down/up and it meant a more expensive control valve and considerably more complex plumbing)

4) I would recommend a double acting piston even though you will only be pressurizing one side of the cylinder.

5) Plumb your compressor to the control valve then from the control valve to the power side of the cylinder. Open the control valve and "BAM!!!" the piston shoots to the other side of the cylinder like a .... well.. bullet! You need to dampen this so it doesn't shoot so fast and has more of a controlled feed.

6) Put a needle valve between the control valve and the cylinder. This will limit how FAST the air will enter the cylinder and limit the acceleration of the piston. The piston will now accelerate a lot slower but will continue to accelerate through the cycle. Now you need to decelerate the piston at the other end of the stroke.

7) Plumb the other side of the double acting piston to a second needle valve then vent the far side of the needle valve to the atmosphere. Now the piston will start to accelerate but the second (cushion) needle valve will limit how fast the air escapes from the cylinder on the opposite side of the piston cushioning the end of the piston stroke.

8) You are ready to go into action. Open the control valve. The piston starts at a moderate speed and accelerates. At about 2/3rds of the stroke the piston will start decelerating. When all the air escapes the far side the the cylinder it will be exerting 110lbs of force on the ram --> pushing the bullet through the die.

9) Release the control valve. The pressure in the cylinder will decrease until the piston / ram starts to rise under the force of the spring. The first and second needle valves will control how fast the air exits the power side of the cylinder and how fast it enters the other side of the cylinder. Giving you a nice smooth upstroke and preventing a return "BAM!!!"

10) The ram won't push the bullet through the die? Increase the pressure from 55lbs to 80lbs??? Higher pressure = 160lbs of force.

11) The ram travels down or up too fast or slow? Adjust the needle valves until you get a stroke you are happy with.

12) Use a foot actuated control valve... this will leave both hands free to work.

13) These are the pneumatic fittings you want to buy on ebay. Just push the tubing into the hole in the blue plastic and the tubing will hold. Push down on the blue plastic and the tubing will be released and come out freely. I have some all plastic connectors that have worked well for me, held up without issue and are a lot cheaper.

8mm-thread-1-4-inch-air-straight-pneumatic-tube-fitting-PC8-01-One-touch-hose-quick.jpg_640x640.jpg


14) Why does the ram in the press in the video have to travel ~3" - ~4"? It seems like 1" of ram travel should be plenty?

Like I said I am no expert, this is just what I have learned from building my powered mortising machine. Take it for what it is worth.
 
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If you need pneumatic fittings just find your local Clippard dealer.

You might start by looking at a Star lube size.
 
My first one was pneumatic.



I use custom size dies I machine in it, held in place by a large double split set collar under the main plate.

If you don’t want to mess with a compressor it doesn’t take much to automate a single stage. This is a Lee breechlock I turned into an auto sizer and didn’t even have to modify the press in anyway.

This one you can get a good view of the shuttle linkage and how it’s operated by ram movement.



This is it sizing



Add a collator and it’s hands free.



That “hands free” part is pretty important, you at least want a feeding device or a trigger that requires both hands to activate. You don’t want any of your digits mashed, that’s for sure.

This is the build thread on the one in the OP.
http://castboolits.gunloads.com/showthread.php?333579-Semi-automatic-sizer
 
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I think I would try hydraulic powered over pneumatic. I worked a lot on Heavy Construction equipment and the only pneumatic systems were bed covers on demolition trailers. Seems more power can be available with hydraulics (fluid doesn't compress like air)...
 
I would use a double acting cylinder so that it goes back under power and doesn't have to fight the spring. What you need to control this is a 5 way/2 position valve.

There are a number of ways to do it.

Electronically like my pneumatic sizer above.

Could use pneumatic “switches” and trigger one to send the ram off and the ram triggers the other to return, have it run “full auto” hitting switchesat both end of the stroke or manually activating them.



Then there is also a spring return and switch that uses half the air and can be pretty quick. Like the one I used for mold tappers on my casting machine.

 
Id like to just stick to hand operated pneumatic stuff. Jmorris stuff is cool but I'm not looking for full automated.
 
Amazing ingenuity! I confess however that watching these videos supports my decision to always use plated or FMJ store bought bullets - LOL
 
That one is pretty outstanding, all he needs is an auto advance on the tubes, maybe even a collater to fill them.
 
If you click the link at the bottom of #17 that is the thread on his manual feeder, in that video.
 
Walkalong wrote:
Those are seriously cool.

I think everyone on THR can agree that the things jmorris builds are "seriously cool" (or beyond).

Some years ago when he complimented my rotary tumbler built using a Texas Instruments printer drive mechanism and a Folger's coffee can, I considered it a badge of honor.
 
That is my video referenced in post #1. It is a single action cylinder. The spring is sufficient to return the ram to the top. It takes 100 psi to keep it from jamming up and that is with a 1.5" cylinder. It actually sizes 233 grain .45acp easier than 9mm 147 grain. I'm certainly no jmorris, my buddy welded up the frame for me. Been using it a couple of years now and have sized at least 15K with it.
 
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