The Numismatic Bibliomania Society

PREV ARTICLE       NEXT ARTICLE       FULL ISSUE       PREV FULL ISSUE      

V13 2010 INDEX       E-SYLUM ARCHIVE

The E-Sylum: Volume 13, Number 25, June 20, 2010, Article 19

MORE ON COIN STRIKING TECHNOLOGY

Dick Hanscom provided this update on his coin striking experiments:

I did another experiment with the drop hammer, pushing it down the runners. Almost got a full strike. I need to make arrangements to really throw it down. I am sure that will do the trick. Sledge hammer did even better, but I wimped out and didnít hit it as hard as I could have for fear of missing!

I played with the new screw press. It punches out blanks (so far up to 32mm, 2.4mm thick for my trial strikes with the drop hammer) and will strike a 14mm token. I'll progress up to see how large it will go with one twirl of the swing arm (I am sure there is a technical name).

Jim Duncan writes:

I'm a collector, not an engineer, but I once watched a man using a drop hammer. Every time, just before he dropped the hammer, he painted the top of the upper die with something. I asked what it was, and the answer was "kerosene". He reckoned he got an extra bit of 'push' as the kerosene exploded under the impact. I can't answer for the efficacy of it, just that he did do it, and reckoned it worked.

Dick Hanscom adds:

Kerosene....hmmmm.... I think my wife thinks I am enough of a danger to myself without adding an explosive. May have to try it.

Dick Johnson writes:

I am waiting for Dick Hanscom to get so frustrated with his home minting kit that he is going to throw something against the wall.

Dick, take your die to a professional private mint and have them strike it for you. They will know what to do and have the proper equipment to do it. I just hope you haven't received your mail order home heart surgery kit yet.

Now how much fun would THAT be? Dick's been working on a revised edition of his book on his coining experiences. Thanks to The E-Sylum, Dick's been in touch with Eric Holcomb. -Editor

Eric Holcomb writes:

Iíve already been in communication with Dick, and weíve worked out a simpler version of the calculation for his book that uses English units from the outset.

This is actually a very interesting and complex problem. As it turns out, Dick has some good hydraulic press data that show why itís difficult to get a good single strike for a coin or token of this size (1 oz. gold), due to work hardening of the metal. As I pointed out, thatís what the U.S. Mint discovered in 1907 for the high-relief double eagles. Would a ďhot strikeĒ be more successful? Ė that would be interesting to know.

To read the earlier E-Sylum article, see: MORE ON COIN STRIKING PRESSURE CALCULATIONS (www.coinbooks.org/esylum_v13n24a13.html)

Wayne Homren, Editor

Google
 
NBS (coinbooks.org) Web

The Numismatic Bibliomania Society is a non-profit organization promoting numismatic literature. See our web site at coinbooks.org.

To submit items for publication in The E-Sylum, write to the Editor at this address: whomren@gmail.com

To subscribe go to: https://my.binhost.com/lists/listinfo/esylum

PREV ARTICLE       NEXT ARTICLE       FULL ISSUE       PREV FULL ISSUE      

V13 2010 INDEX       E-SYLUM ARCHIVE

Copyright © 1998 - 2012 The Numismatic Bibliomania Society (NBS)
All Rights Reserved.

NBS Home Page
Contact the NBS webmaster
coin