De rim 22 brass air cylinder press

[COUSIN DANIEL]

Can anyone offer an idea of the pressure required to de rim a 22rim fire case?

I want to get a air cylinder to speed up this process and take the strain out of my neck and shoulders.

[dimaprok]

I made one recently. It was on my To Do list for few years. Very happy the way it turned out. Picked up used cylinder on ebay cheap. My struggle was trying to find the right hose connectors; went to local pneumatic store and they hooked me up and bought plastic hose there too. Knowing which connectors I could use I ordered air valve controller on Amazon and found a 12v power adapter and tempory switch that I wired to some scrap bracket. I also ordered a moisture filter and boy does it collect water! About 1oz in 15 min.

I was debating if I should sacrifice my Lee Chalenger press or make my own fixture to hold a die. I decided on later. I machined two rods, drilled and theaded so they would screw on protruding studs that hold cylinder together. For the top I got inspiration from my Corbin Sea Girt press. Cut a piece from scrap rusty metal plate I had that I drilled and bored and threaded on the lathe.

It does consume a lot of air so my compressor is running non-stop. Federal heavy cases take between 110-130 PSI and there is a pause when I get one until compressor catches up. With regular 9+ grain cases I can go non stop, it takes about 90 PSI.

Now this can vary depending on your die and punch diameter.

https://youtu.be/dNRYn_Bkjjs

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[dimaprok]

Forgot to add for the punch I took automotive bolt that I machined into punch, I took pneumatic cylinder apart which turned out to be very simple (4 threaded rods and 4 nuts holding it together) There was a large thread on the ram that was of no use to me and made it stick out unnessesary, I chopped off about 2" and drilled and tapped to accept punches. At first I used the punch as is and noticed it was getting wear, so heated up and dunked it in water and now I don't see noticeable wear.

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[Ajax111]

Very nice! I see most of the systems are Pneumatic.

Has anyone used other systems to take out the rims, like Hydraulic/Electric?

[Lakehouse2012]

We use hydraulic, it's overkill in our case but it's the pump we had laying around. About 1000psi...

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[Ajax111]

I have a couple of shotshell reloaders using Hydraulic systems.
I'm not sure how much pressure they build, but it might be worth a look.
Thanks

[jmorris]

Can anyone offer an idea of the pressure required to de rim a 22rim fire case?

Takes just over 600 psi of force to derim an unannealed, Winchester super X case lubed with Hornady unique lube.

[JRLesan]

Pressure to de-rim would be entirely dependent on size of pneumatic cylinder; bigger cylinder= less pressure= more air delivery.

[Sitzme]

Former machine designer with 25 years experience here. Please use a 2 hand switch or work by your self. If you get tired or distracted that punch will go through the part of your hand that is in the way. All the screaming is irritating to the others in the room!

I know, you will be careful and so forth. You might get away with it, but it is not good practice. Whatever you do, be aware that if you sell or loan out the device it could come back to haunt you if there is an accident.

Having said all that, if you go a bit oversize on the air cylinder and set the pressure regulator to the min needed, you can reduce air consumption. Dial the psi down to where it barely works and then increase 10% or so until it always works. There is another device called a quick exhaust valve that can speed up the retract. This is OK unless you want to use low psi air for the return stroke. This would greatly reduce the air consumption but at the cost of complexity. I suspect for most hobby use a simple valve(s) is going to get the job done and the air waste gives time to refill the coffee or some other task. You can also add flow controls to the cylinder to get smooth motion and variable speed on each direction. These I do recommend but again they are not absolutely necessary.

[IllinoisCoyoteHunter]

Yep depends on size of cylinder.

[jmorris]

Pressure to de-rim would be entirely dependent on size of pneumatic cylinder; bigger cylinder= less pressure= more air delivery.

Pressure required to push the brass through is not effected by the cylinder, how much pressure you can get from a given PSI can be changed by piston diameter.

My test was using a valve spring testing gauge, just reads in pounds per square inch the force being placed upon it. It’s peak reading was just over 600 psi. Not completely unlike stepping on a scale. Doesn’t matter if gravity is pushing, air or hydraulic as I was using. It was just how much force it took to move the case past the smaller OD.

How you get that amount of force may be dependent on air pressure you have available. If you have 1200 psi you could use a cylinder with 1/2 in^2 area. If you only have 100 psi it would take a 6 in ^2 piston area to get you 600 PSI out; however, none of that effects how much force it takes to shove the brass through a die.

[IllinoisCoyoteHunter]

Too many variable really. Diameter of the sizing die, entrance geometry of the sizing die, diameter of the punch, and variations in wall thickness with various headstamps are a few variables.

[jmorris]

There are for sure, even the condition of the case, annealed or not would have a substantial effect. Why I stated the pressure required for the specific case, lube and condition, I used.

With annealed cases, I would expect it to require less force, for example.

That said, of the variables, air cylinder size isn’t one of them.

[IllinoisCoyoteHunter]

Air cylinder size becomes a variable depending on how much output pressure you have. The pressure to push the case through generally stays the same but your success will vary if your equipment isn’t up to the task….obviously lol.

[Misery-Whip]

Not suggesting i reccomend the modification of a nailgun, but the volumes and pressures it uses to function could get you started. Thinking a roofing nailer or framing.

[jmorris]

Air cylinder size becomes a variable depending on how much output pressure you have. The pressure to push the case through generally stays the same but your success will vary if your equipment isn’t up to the task….obviously lol.

Yep, first sentence of #11.