Messages

Subject:
Re: Kanefusa (long)
Response To:
Re: Kanefusa *PIC* ()

Larry Clinton At Frankfort, (Central) Indiana
I am an "old" Engineer. Therefore I have seen the evolution of both the skill level of toolmakers and equipment design!

Don't believe that the same "quality" and accuracy could not be achieved with the 1930's ~ 1950's equipment as with the new "super accurate / precision machines!

However, in the 1950's years of experience and great skill were required from a toolmaker to get the required accuracy from the old machines. Often many more man hours were required to obtain this accuracy.

Much of the improvements in Equipment were driven by economics, this meant reducing the time to produce an acceptable product with far less skilled operators.

A CNC mill really only requires that the operator is skilled in programming, and basic knowledge in machining (IE: what tooling cutters to use, sequence of operations, speed of travel, proper mounting of item to be machined etc.).

The old mills required knowing how to take up machine
"backlash", proper feel for the manual feed rate, repeated measurements during the machining operations, cooling time required and a myriad of other items (many beyond my knowledge and /or skill level). Surface grinders required knowledge of wheel choice, proper balancing and dressing of the wheel etc.

However I have seen many gages produced with the "old" equipment that checked within .0001 or less! However these gages were not made with apprentice toolmakers - which they can do with the equipment of today.

Much of this is like the evolution of furniture building. A table and chair set of the 1800's with good quality could take many man hours of work by a very experienced woodworker and cost months of normal wages for the average worker. Today the same quality of the above can be done in a modern furniture factory in a fraction of the time (and cost).

An interesting story (to me :>) was that in the late 1960's our company purchased several "spiral cutting" machines from a company in Germany. These auto fed a ceramic resistor body about 1/8" diameter by .300" long into chucks that rotated, then a carbide or diamond high speed cutter wheel lowered on the rotating body and cut through an electrically resistive metal film that was deposited on the body in a vacuum chamber as it rotated causing a spiral pattern, this raised the resistance of the film to meet the 1 percent tolerance in a specified measurement of resistance in ohms.

To make a long story short, shortly after putting these machines in operation wear items began requiring replacement, normally a quick job. However we found EVERY machine was built differently! Shafts to bushing fits were very tight (within .0002") however the shafts diameter varied by .002" or more between machines.
Nothing on the machines were standard, things like base mounting holes etc. varied widely. Apparently each machine was built by an individual with basic instructions. We kept a toolmaker in our shop busy making replacement parts!

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