One of several causes of off-center strikes
RogerB
Posts: 8,852 ✭✭✭✭✭
This letter mentions one of several causes of off-center strikes. If you read the JNR article, other potential problem areas will become evident.
[RG104 entry 17 box 2]
Mint of the United States
Coining Department
Philadelphia, Pa.
May 11, 1893
Hon. O. C. Bosbyshell,
Superintendent
Sir:
The thread in the holes in the cast iron head of the Ferracute coining press, where the long bolts run through the arch to hold the upper dies has torn out – this permits the die holder to move about and consequently the die does not strike the center of the planchet. The thread seems to have been too short in length to hold.
A new head will have to be furnished and the Ferracute Company had better send here and see what is needed.
Very respectfully,
W. S. Steele,
Coiner
[Ferracute Company made large machine tools including coin presses. Patents were held in the name of Oberlin Smith. See JNR issue No.1 for their 1896 toggle press patent and drawings showing the press parts mentioned in the letter.]
Comments
Does that mean the dies would not line up properly and partially strike whatever was around the planchett. This might be a little hard on the dies if they struck something like cast iron.
Yep. The upper die would hit the collar, which was hardened steel just like the dies. Fortunately, the collar had a leaf spring support to prevent too much damage. Still, not a good thing.
This sounds more like a misaligned die than an off-center strike.
Ed. S.
(EJS)
Misaligned seems to imply incorrect die setup, while the letter indicates a defect in the machinery. Of course, the final result might appear the same.
Thanks for your research.
So when the pressure is not held and the energy finds a weakness, it causes problems with strike, alignment & perhaps metal flow. Sort of like a nail, if not held properly, the force of the hit can cause many issues.
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Yep.