[TR] How do they manufacture gears?

[John Macartney]

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