Striking 19th Century Master and Proof Coins
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2 posts in this topic

This will be a quick and painless vaccination against numismatic bologna.

The Philadelphia Mint had a large screw-type (“lever”) press used to strike medals and proof coins. “We use a screw press which strikes medals from 10/16-inch to 4-inch in diameter, which has 3 threads with a pitch of 1-5/16-inch; 6-1/2 inch diameter of screw, and length of lever 15 feet with 300 lb balls on each end [1886].” No other mint had screw presses and no branch mint had ever had them. This press was used to make Master coins and proofs from the 1840s to 1893.

The press took three men to operate. One placed the planchet on the lower (fixed) die and the other two swung the 15-foot lever, attempting to use the same strength each time. Striking pressure was varied by reducing the weights, or positioning them further toward the central screw, or adding/removing a spacer below the lower die to change the distance the upper die moved.

After each strike, the operator who placed the planchet removed the coin and added it to a flat tray lined with paper or sometimes cotton-lined paper. This was periodically collected by the Medal Clerk or an assistant, for inspection and sorting.

Coins which were deficient in polish or included minor blemishes were put aside and later mixed with normal toggle press pieces. Defective coins, i.e., ones that would be rejected during normal circulation coinage, were delivered back to the M&R. Good proofs were placed on trays and packaged just before delivery. Packaging was similar to medals: cotton-lined envelopes, when available.

Most proofs were sold at the Philadelphia Mint by the Treasurer or later the Cashier, who received them from the Chief Coiner or Medal Clerk.

Finis.

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On 2/24/2022 at 4:47 PM, RWB said:

This will be a quick and painless vaccination against numismatic bologna.

 

The Philadelphia Mint had a large screw-type (“lever”) press used to strike medals and proof coins. “We use a screw press which strikes medals from 10/16-inch to 4-inch in diameter, which has 3 threads with a pitch of 1-5/16-inch; 6-1/2 inch diameter of screw, and length of lever 15 feet with 300 lb balls on each end [1886].” No other mint had screw presses and no branch mint had ever had them. This press was used to make Master coins and proofs from the 1840s to 1893.

 

The press took three men to operate. One placed the planchet on the lower (fixed) die and the other two swung the 15-foot lever, attempting to use the same strength each time. Striking pressure was varied by reducing the weights, or positioning them further toward the central screw, or adding/removing a spacer below the lower die to change the distance the upper die moved.

 

After each strike, the operator who placed the planchet removed the coin and added it to a flat tray lined with paper or sometimes cotton-lined paper. This was periodically collected by the Medal Clerk or an assistant, for inspection and sorting.

 

Coins which were deficient in polish or included minor blemishes were put aside and later mixed with normal toggle press pieces. Defective coins, i.e., ones that would be rejected during normal circulation coinage, were delivered back to the M&R. Good proofs were placed on trays and packaged just before delivery. Packaging was similar to medals: cotton-lined envelopes, when available.

 

Most proofs were sold at the Philadelphia Mint by the Treasurer or later the Cashier, who received them from the Chief Coiner or Medal Clerk.

 

Finis.

 

Hmm. In retrospect, cotton lined envelopes may have caused hairlines, no? But in that era, what better options were there?

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