all of these factors as we look aj the various types of varieties that were produced over the years.

 

A number of the plaster models are made and worked on so that the best possible model is produced. Today they make a negative rubber mold into which epoxy is poured. The epoxy forms a very durable model which is known as the galvano. This process was modified over the years. Earlier galvanos were once made of copper-coated shells which were given a lead backing to make them more durable.

 

Here we see some finished galvanos. This photo was taken during a trip to the Philadelphia Mint in June of 1998.

 

Since the galvano is too large, the design must be reduced in size to that which will be used on the dies to strike the coins. This is accomplished by plac- ing the galvano in a machine known as a Janvier Re- duction Lathe. It is a pantograph with two arms. As one arm traces out the design on the galvano, the other carves it into the face of a steel rod. The face of the steel rod is the exact size of the coins that will be struck with that design.

 

The Janvier Reduction Lathe can transfer the design either in relief (raised) or incuse (depressed) into the face of the steel rod. Despite this, it is almost always transferred so that the result is a relief image. The process of transferring the design from the galvano to the face of the steel rod is a slow and tedious one. It can take anywhere from a day and a half to two days to transfer the design. When completed, the face of the steel rod looks just like a finished coin with that design. This steel rod is known as a Master Hub.

 

May/june 2004

 

 

In this photo we see several of the Janvier Reduc- tion Lathes in use at the Philadelphia Mint. The round white objects at the centers are the galvanos.

 

 

Here we have a close-up of a galvano for the 1999- S proof Kennedy half dollars as it is centered in one of the Janvier Reduction Lathes. Remember that our trip to the Mint was in June of 1998, which should give you an idea of how far in advance they have to begin producing the dies for the following year's coin production.

 

 

In the same Janvier Reduction Lathe we see the steel rod that is being transformed into a Master Hub for the 1999-5 proof Kennedy half dollars.

The HUB 5