What are these operating devices? There are several styles of stamp mill operating devices known as keys, paddles and other various names. These devices are used to start (drop) and stop (reset) the stamps on stamp mills. They are basically a wedge device that is forced between the cam and the tappet to lift the tappet off of the latch finger and start that stamp operating. Each stamp is actuated individually with the key. I have visited many mills that have original style operating devices and they are noted below:
I have taken the best of the designs and applied it to a device that can be used to release and rest the stamp on an operating stamp mill. There are several items that are needed to make a key and are in the picture below:
The diagram below is labeled A through E and shows the major steps to assembling a key. The materials that are not shown in the diagram above are the rubber melting material that is ½” thick and the wood paddle made from a 2X4 that has been planed down on one end and the handle cut out of the other end. The pictures below of the materials should give you a good idea on how to construct the rubber. ]
NOTE: Make sure the handle is not too thick as it may be difficult to keep a good grip during the release and reset process.
The picture below shows how the key is used to start the stamp mill. The millman places the key between the rotating cam and the tappet and waits for the cam to lift the tappet up and then pulls the latch finger back and releases the stamp. This is done for each of the stamps until they are all in service.