Posted by pcb1962 on 24/08/2013 10:51:02:
On the point about your son, I'm not sure if the analogy of learning to drive an automatic car without learning how to use the gears applies. Using a manual lathe enables you to learn about feed rates, depth of cut, how different materials behave etc in a way that cannot really be learned from books.
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I can explain this.
At one time I would have said the same but an encounter with the CNC turner up the road at the Aerospace factory changed my mind.
One day whilst i was screwcutting he called round to borrow something, stood at the door watching and when I'd broke off said "I'd love to be able to screwcut "
Amazed I queried why he couldn't and the reply was he's never used a manual lathe in his life. So I asked how they went on when they got a new machine with a controller they had not seen before.
Answer was they usually got 1/2 days training when it was commissioned and then they were on their own.
I asked him at what revs he screwcut parts and the answer was 2,500 because that was as fast as the lathe went.
Because the carbide tooling could always stand the speed unlike HSS, speed was never a problem so everything ran flat out and feeds / depth of cut were adjusted to suit materials and jobs.
So basically they are no way related but it's just a different learning curve between manual and CNC disciplines.