Toggle-type coinage presses had no….

[RWB]

...pressure adjustment in the conventional sense. There was no pressure dial or wheel to turn.

 

In a toggle press, like the one invented by Franklin Peale in 1835, the same amount of force was produced with each cycle of the press. So, how could the force used to strike a coin be altered for coins of different sizes?

 

In Peale’s press, the upper die fit into a die chuck. This was tightened and locked with a steel pin. The die was not supposed to wiggle within the chuck. Above the die chuck was an adjustment wedge controlled by a threaded bolt. Turing the bolt moved the wedge and this altered the space between the toggle’s ball joint and push rod, and the chuck. This, in turn, increased or decreased the travel of the upper die and altered the force applied to the planchet as a coin was struck. The wedge was locked in place using a steel pin or screw.

 

[grip]

(thumbs u

[Crohnos01]

I am guessing that this process required a few "trial and error" runs to get the setting correct each time the planchet size was changed?

[RWB]

The die setters probably had a "cheat sheet" similar to ones used with the rolling mills, but I expect there are several test pieces made before letting the presses run full-tilt.

[RWB]

PS: Yes, there are drawings in the From Mine to Mint book. You can also see something similar in the Autumn 2012 JNR issue in the article about the Smith press design.