I dunno the reason for the dies not starting, but there are some really poor
quality die sets on the market and for China/India standards, the products
just looky-like dies but are barely sitable as thread chasers for cleaning
up a slightly damaged good thread.
Almost always, the side of the die that's marked with the size is the
starting side and the exit side doesn't have the widened opening for
starting onto the workpiece.

Also, the end of the workpiece should have a fairly uniform chamfer which
aids in starting the cutting action.

If no cutting action can be felt in the first 1/4 to 1/2 turn, it's likely
that something is wrong.. either the quality of the die is very bad/damaged,
or the workpiece is excessively oversize (assuming that the workpiece isn't
hardened steel).

--
WB
..........


wrote in message
...

I have die holders for the lathe. I tried them and could not even get
the thread started. I tried pushing with the tailstock. I tried brute
force by hand. Not a thing.

As I see another one of these in the near future followed closely by a
need to cut 3/4-16 I shall have a go. I suspect the whole thing will
be done manually as I have no confidence of my ability to stop the
lathe at a speed of 150 rpm just at the right moment.

BTW I have developed a great liking for carbide tools but I see that
for this job HSS will be better.

Michael Koblic,
Campbell River, BC