"Richard J Kinch" wrote in message
. ..
How do you get a clean start to outside threads cut on a lathe? For
example, if you threaded the outside diameter of a rod, where the end of
the rod had been perpendicularly faced, a geometrically perfect thread
would end in a knife edge. Simply chamfering the corner doesn't really
get
rid of it all. Ideally you would want the thread that just suddenly ramps
up out of the minor diameter, like is formed on the end of a common
commercial bolt.

Um...file it down? It's not something that goes 'round and 'round so you
can't really turn it. Although I suppose you could try like, cutting a
tapered thread at the same TPI but on the peak of the thread, so as the
carriage advances, it's timed to clip just the very leading peak of the
thread, then the taper makes the cutter fall away in 1/2 or 1 revolution.
So you'd have a taper that goes from minor to major diameter in 1 turn...

Tim

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