Press or ? to make coins

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I have been looking into making coins. From what I have read I need upward of a 100 ton press and most likely in the 500 ton range to make a good impression. I was hoping to go at it from the other end with softer metal, like annealed copper or aluminum. Other thoughts are use of other machinery besides a hydraulic press. My plan was to use my 20 ton shop press, but it may be on the small size. Right now I don't have room for a 500 ton press that weights 50,000 pounds even if I could afford it. I was hoping to avoid the CNC or cast route and make more than one a day.
 
I've seen machines the turn a penny into a souvenir medallion in several museums. I believe that the coin is run through a hand driven rolling mill. It wouldn't seem likely that 100 ton+ forces are involved. I don't know how crisp the image is though.
https://en.wikipedia.org/wiki/Elongated_coin
 
At the fair and other weekend events there sometimes are coin makers that do it old school.

Newton works ...

A set of dies are used to create the coin and a very large chunk of steel or stone weight is hoisted up a set of rail tracks then allowed to fall onto the dies.

You only need the force to create the form and not to hold anything so the power needed is high power low time.

Lots of complicated math but simply put...Just soak it with something heavy.

Taller fall requires less weight.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 
wawoodman said:
And besides, the US Mint hates competition!
Click to expand...
OUCH!!!

A place I used to work at, we built presses to straighten large steel bars on, 400T and larger. One of the guys that worked on one of the presses took a half dollar and squashed it into a silver dollar size coin. Well, it wasn't perfectly round, but got it down to pretty thin! Took a oak 4 x 4 and loaded it up end wise and turned it into "tooth picks at about 200T. :eek:
 
I made parts here for a shop to be swagged onto cables and used as Jet Engine Hoist Cables. 316 Stainless on 1/2 dia. Stainless Cable. The Press swagged them on at 360 tons. None ever failed.

"Billy G"
 
I don't think you need a 100ton motorized hydraulic press to make coins. Should be able to do it with a BFH.

Or you could do like this guy. "entertaining" video. Read the comments for a good laugh.
 
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The stroke needed to strike coins is very short, say the impression depth is .020" per side it then only requires force through a .040" stroke, it only has to open enough to insert the blank then remove the finished part, such a machine would only be useful for that operation. If this is all that is required then it is an excellent design that requires low power to operate.

Shut height is critical so provision must be made for adjusting it accurately or bad things happen.
 
thanks for the ideas. I'll keep on experimenting. I like the roller mill. I thought about the hammer. A trip hammer or power hammer works out to about 5ish tons. I might have to dust off my physics book, to see what the energy is. Energy reguirements might be the better question.
 
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