Here is the drive I came up with for an 850 clock. It is made with a couple of computer gears, bushings a couple of collars and a drive. The mount plate uses the clock mount bolt pattern for mounting. I plan to use the hex receptor drive off the bottom of the clock and stop the drive rod just inside the skin so through a small hole, a hex rod on a crank handle can be inserted to actuate the clock.
The big gear from the computer will only turn one way to keep anyone from driving it backwards, the bottom half of the gear is bolted to the mount plate.
In order to work correctly, the reset has to be loaded, so it returns it to the starting position after resetting the clock.
I got a spring at Home Depot for the reset......
The 850 reset spring is wound clockwise but all the springs I looked at were c-clockwise, it still works though...The hole on the face mount that the spring goes in was terminal so I left the end long and it holds against the bottom plate.I had to remove a link from the chain due to excesive slack.I loaded it with 6 turns backwards then replaced the chain on the gear then adjusted the tension plate
I rebuilt the (heavy duty...yuk-yuk)on/off switch to run the lights.
I am just doing the mechanics of this pump so it will be off to the customer soon.