one stroke, psi to punch check?

[edsmith]

Does any one know how much pressure it takes to punch out a check with a single stroke check maker? I am going to try a bathroom scale and a drill press, but don't know how accurate that will be. need to know so I can figgure out a size for a air piston press. thanks guys

[taminsong]

Wow, I'm thinking that you will going to automate the checkmaker? Nice!

[edsmith]

Yea, at least I am going to try. I want to make one that is easy to make, no lathe or milling machine needed, off the shelf parts. I want to make it out of PVC and also a metal version, not sure if a pvc one would stand up under the strain. I have the piston figgured out, the valve is the biggest problem. I want the valve to be activated by foot or knee or hand.

[Sonnypie]

Sure Ed, It takes THIS MUCH. <click here<

And don't use your bathroom scale.
Unless you really want to buy a new bathroom scale....
IF it doesn't mash the pee-doodley out of it, the shock load/unload of the punching will spring the mechanism to death.

Looks like about 4-5" diameter will make a lotta squish.

What I wonder about is the force when an Air-Arbor press breaks through? Does it slam the die down? Does it need a shock absorber to stop the ram before it bottoms out the die?
Hydraulics are pretty absolute. But air can be real springy.

And DO NOT use PVC!
PVC piping or components are NOT to be used with compressed air.
Plastics can, and have, exploded under air pressure and even killed people working nearby.
PVC can go off like a grenade and send shards of it out like shrapnel.
Here is more about that.

You are too nice a guy to let you go blow yourself full of plastic shrapnel.

[edsmith]

Thanks, sonny.I am a plumber and have used pvc for pressure lines, but in this case, PVC is out. I will stick to steel. with the piston at chest level, good way to meet your maker. a 3" piston should give me about 500lb.the bathroom scales said to thank you for saving it's life.

[Sonnypie]

Thanks, sonny.I am a plumber and have used pvc for pressure lines, but in this case, PVC is out. I will stick to steel. with the piston at chest level, good way to meet your maker. a 3" piston should give me about 500lb.the bathroom scales said to thank you for saving it's life.

Ya know Ed, you might be able to use a cylinder hone to slick up the bore of your cylinder without too much expense.
Just a though.

Here's some valves.

[scrapcan]

ed

you might have a look at surplus center and their pneumatic section. They may have some very reasonable components to make a set up.

[Jim Flinchbaugh]

The one I made one not take any where near 500 pounds.
Sonny is right about the PVC pipe, I've used it for air lines as well, but if you are 'shocking: the system with short bursts it aint gonna last long and end up with something stuck in your forehead. There are adjustable controls for applying & releasing air pressure.

[Alan in Vermont]

Pneumatic operation is NOT the way to go for something like this!

Once the punch has broken the slug loose the resistance waill drop to virtually zero. At that point you have a serious load of compressed air which will instantly slam the piston to the end of the stroke. Without some sort of buffer in there the moving parts are going to run into the fixed ones and hammer things to pieces in short order.

Even if you had a foot pedal that would dump the air instantly upon release you couldn't get off the pedal fast enough to prevent the cylinder hammering things.

Hydraulics would work but hydro systems are are pricey. Hydraulics can move slowly and still develope the power to operate a punch smoothly and with far more power than an air cylinder of a given size.

[tjones]

Excellent point. What about limiting the length of stroke so nothing bottoms out in the dies. Of course, the shock is absorbed somewhere in the press piston jug.
tj

[edsmith]

It is going to be a spring return piston,with a thick rubber disk at the bottom, hydralics is out, just too much cost involved, and too much gear, pump, high pressure hoses,cylinder, valve, air will do. the only way to know for sure is to try it.

[Sagebrush7]

Buy you an Air Mite press. DAP7-2 up to DAP12-2. Anything larger you will smash your dies. The towers are adjustable for height. You do not want to bottom out the die. You regulate the air for material thickness. Three inch cylinders work up to 44 calibers. Need 4" cyliders for the big calibers. You can purchase on EBay sometimes as cheap as $149.00 plus shipping.

[edsmith]

I have priced the material to make an air cylinder, for a 2" it would cost around $60 to $80 bucks,so thanks to manleyjt I went to surplus center, a 2" single action,spring return,250 psi max air cylinder for $16.95 I will be using that, the control valve is $6.95 manual or 24 volts. I think I will get one of each to fool with.I wanted to keep this project at $50 or under, I think I can do it. I have no intrest in buying a ready made air press, not for $150. I figgure if nessary I can kick up the air pressure for the larger checks.I see no reason why an air cylinder would'nt work,they work for mity mite. I do this stuff because this is a DYI forum, if I wanted to buy already made stuff I would,for those who think I am a idiot for wanting to make these things,why do you cast boolits, you can buy them already cast.the cylinder looks good, it has a 1" stroke,it is adjustable, so you won't be wrecking the dies. so now the hard part is going to be making a low cost sturdy frame.

[Sonnypie]

I had a brain fart, Ed.
Under my RV is a couple of Firestone load handlers. The factory stuck those on.
I updated the whole thing and added front air bags, and a control panel with these little switches that control air to the front and rear, with a dual needle gauge.
Point is...
These things just sit down there in the worst of conditions and do their job. Nothing around them, just a squish-or-push controlled force.
Seems one of them could sure do an actuating job in a fellers shop.

I know Sagebrush7 actually uses the AirMite presses in his operation.
People would do well to pay attention to him. He knows what has worked for 100's of 1000's of gas checks.

Automation is not for those who have trouble with the toilet paper roll....

[Sagebrush7]

I don't think you are a idiot! I will not offer any more suggestions.

[looseprojectile]

If that is what you are doing.
An electric solenoid works for the old Wales Strippit machine.
I have spent several hundred hours punching holes in sheet metal.
Start out with an angle or curved face on your punch or die so that it punches progressively.
Takes a lot less effort.
That is all I got.

Life is good