Force required to mint a quarter

Hello all. I'm a mechanical engineer at tufts university. I have a project in which we need to know the force required to mint a us quarter. If anyone has a rough number with some validity that would be excellent.
Thanks!
-Nate

 

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If you look inthis thread you wil see what was used. "Well, fellow Numismatists, it happened. The United Staes Mint sold two of it's 400 ton triple-striking HME Model K-360 proof coin presses to the New Zealand Mint, the only private special metals mint in New Zealand.(They now are installed in the showroom of the mint's Auckland premises)." I would guess that this is more than "required, but it is what was actually used - for proofs anyway.

 

I'm not sure if I can assume that that is for quarters, even though it is the highest force press that I have found in my research, and force required is proportional to coin diameter.

 

360 tons???
http://inv.buyused.com/q/webinv/003411=iform,,0P5675,,list,,,00866832,,

 

im leaing towards HME's 400 ton press, but i wish I had more to go on than a hunch

 

This might help?

Coin Talk - The Place to Discuss Coins > Coin Forums > Coin Chat > making coins

See this thread. Tom talks about the force to make a quarter size coin here.

Good Luck

Darryl

 

I found a link that says cents are struck at 40 tons and larger coin are proportionately more.click here

 

FYI: It says"Pennies require about 40 tons of pressure, and the larger coins require proportionately more." Not 400 tons. I would guess that the press sold to New Zealand is capable of minting cents trough dollars (as in Ike size dollars) and it is an overkill for the dollars.

 

does a 400-ton press deliver 400 tons of pressure? And, I would GUESS that the PSI is the way to measure the 'force required'?

 

Im guessing a 400 ton press delivers 400 tons of force, if it was pressing something 10 sq. inches i doubt it would deliver the same pressure as if it was pressing something 1 sq. in.

 

The 400 tonns is a unit of force. PSI is force per unit area (pressure). If it were applied to 10 sq. inches, it would be 40 ton per sq. inch (80,000 psi). The force required to mint a coin would be proportional to the size of the coin. The psi required would be appoximately the same for any size coin.

 

yeah i understand that, im talking about the rating of the machine though, if a machine is rated at 400 tons im assuming on a 1 sq. in. coin it would be 400 tons/sq. in or 800000psi, i doubt that same machine would deliver 800000psi to a 10sq.in coin, most likely 80000psi, but I could be wrong, it depends on the rating system. Regardless, I'm hesitant to say 60 tons of force to mint a quarter, I was quoted a rate of 750 coins per minute, cold forged, without lubrication. I wish the US mint wasn't so tight lipped about it but i suppose its information they don't want everyone having. Thanks for all the help everyone. I'm still searching for something more definitive.

 

First, a 400 ton pres can deliver 80,000 psi to a 10 sq. inch dye BY DEFINITION.

Your best answer so far is vipergts2's site. A penny is 19 mm. A quarter is 24.3 mm. A penny "requires" 40 tons. A quarter requires proportionally more. Therefore, a quarter requires 40 X (24.3/19)^2 or 65.4 tons.

 

You also should be adjusting for the thickness and hardness of the planchet. An all silver half dollar would in theory take less pressure to mint than a clad one.

 

Well if you just want a rough number, between 30 and 100 tons depending on the denomination,
the source for those numbers is taken from here: http://www.camacs.com/coin_info1_minting_process.html
I can't guarantee the accuracy, but it sounds fairly reasonable, and at least its not a Wikipedia site!

 

Not that I am disagreeing woth you, but where sis that number come from?

 

Most US copper nickel clad quarters at struck at about 65 tons (130,000 Lbs.).

Proof set quarters are at around 70 tons and mint set at 75 tons.

I'm not certain that this is total force rather than per square inch.