Revamping the Cincinnati Milling Machine

One of our most useful pieces of equipment went down on us last year.  After many years of faithful service, the transmission gear box failed.   It is one of our new machines, housed in the Tri-Dam building, so most visitors do not see it.  Keep in mind that the term ‘new’ is relative, here.

The Cincinnati #4 Horizonal Mill with Powered Overarm, Circa 1954, is new, in comparison to the machines in our historic belt-driven machine shop, but in 2012, most folks would not consider it new.  This piece of equipment came to us around 1993, from miliary surplus at Rough and Ready Island.  It is heavily used in the shop, for everything from milling the crosshead guides on the No. 3 during restoration, to boring brake adjuster brackets, to re-boring couplers. 

Its a very useful light-duty powered overarm mill.  The overarm is an accessory which essentially converts the horizontal mill into a vertical mill, as needed. 

Our cohorts at the California State Railroad Museum picked up a heavy-duty overarm at the same time we aquired ours, and its been in storage ever since.  This one is about twice as heavy as our old one, but we were able to get our hands on a factory print of the circuitry.  Our district’s amazingly gifted electrician, Steve Spath, rewired the crunchy old motor leads, and designed custom electrically controlled circuitry.  In early February, Steve spent two days with George &  Phil, in the shop, where they installed and tested the new arm.  Just like new!

The old overarm attachment, ready for retirement.

Steve Spath puts finishing touches on the electrical for the "new" overarm attachment.

Voila! The replacemnt arm in position, and ready to go.