"Ed Huntress" wrote in message et...
"Kirk Gordon" wrote in message
...

Yeah, it's a lie. The beginnings of NC/CNC were done by a couple
guys in a tool shop in Traverse City, Michigan.

That was Parsons Corp., Traverse City. They were producing helicopter-blade
templets with the aid of an IBM 602A Multiplier, calculating positions and
then setting the machine to those positions by hand.
....

Ed and others, thanks for the interesting thread. Like many
innovations there clearly were multiple paths involved. Here are a
few related ones at least worth mention.

The Jaquard looms go back almost 200 years, punch-card controlled
weaving machines. Interesting topic in itself, along with Babbage and
his mechanical computing machines. Side note, you might enjoy Gibson
and Sterling's sci fi book "The Difference Engine".

Few folks in this group under 40 may know what an automatic screw
machine is, how they work or that they go back at least 120 years.
Not that I know more than from reading a book. Bunch of change gears
to set feed rates and cycle timing, and hand-cut cams to cycle through
changes of tools, feeds and stock advance. Net result is loading a
20' bar, then coming back in 20 minutes to empty the bin of whatever
part it just made 300 of. Need a turned length of .750"? Set up
change gears for a cycle that feeds at .010" per rev and cut a cam
that dwells on that cycle for 75 spindle revolutions. Something like
that. Pretty darn close to numerical control. Efficient enough
overall they are still in use all over the world today. The older
Machinery's editions have sections on programming them.

While I know almost nothing about them, some pretty fancy
cam-controlled milling machines were developed either side of WW2.

I'm not arguing that any of this is in any way the equivalent of
direct numerical control, just that it was a long evolution with many
overlapping concepts.

Hydraulic tracers also evolved roughly in parallel with NC and
co-existed for a few decades before becoming "mostly obsolete".
Still used here and there. Tracing goes back around 200 years,
probably to the gunstock duplicating lathes in Whitney's factory that
produced government muskets in the early 1800's.

Hydraulic tracer duplicating mills and lathes were a mid 20th century
innovation, the new concept being the servo mechanism that allow a
stylus to follow a template using very little pressure, while rigidly
controlling a lathe carriage or mill table applying hundreds of pounds
of cutting force.

Tracing and NC were both driven by the need to mass-produce parts
having complex contoured surfaces that could neither be expressed with
simple specifications nor be milled or turned using straight feeds or
specially shaped tooling.

Some of the first practical NC machines were based on hydraulic tracer
machines because the feed control mechanism was so close to what NC
needed.

Bob