Casting my mind back to my Apprentice days (early 60's) the gear cutting
machines at both
Standard-Triumph and Jaguar would machine a gear from start to finish in about
two minutes. The
blank was held vertical but at an angle to the cutter (to create the helix)
which moved up and down
at very high speed with each 'pass' shaving off a little more metal. When it
reached the required
depth, the machine rotated the gear blank a few degrees one way or the other to
start the next cut.
It was quite difficult to see the actual cutting process as the gear and cutter
had a continuous
baptism of stuff we called *suds* which was simply a very lightweight cutting
oil mixed with warm
water. This obviously kept gear and cutter cool and the swarf was retained in a
large catch-tank.
Upon machining completion, the finished gear was washed in lightweight oil and
then dropped on to
special racks for heat treatment.
I'm sure modern machines are far more sophisticated but the ones I operated (or
over-saw) were
entirely automatic and would cut six gears at a time.
On a related theme, I remember a group of Japanese visitors from Toyota
watching me when I was
machining a Jaguar crankshaft (again automatic) and one of them was clearly
fascinated at the
intense blue colour of the swarf coming off the tool - and he picked it up to
examine it more
closely!!!!!!!!!!!!!!!!!!
I suppose the 'loss of face' he would have suffered at the hands of his
colleagues stopped him
yelling out in agony with burnt fingers - but all he did was to flick the swarf
back and utter a
sound of "Haaaaaaaaaaaaaaaaaawwwwwwwwww" Then he plunged his hand into a pocket
and kept it there. I
*almost* felt sorry for him.
Jonmac
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