开云体育

G'day Ed.
Firstly, congratulations on giving it a go.
You haven't told us whether you are cutting imperial (inch) or metric
threads. For the moment I will assume you are cutting imperial with an
imperial lead screw.
Firstly make sure the thread chasing dial pinion engages the lead
screw, a screw in the side of the dial block allows the pinion to be
swung into the lead screw.
As you traverse the saddle the dial will rotate, also if you drive the
lead screw without the saddle moving the screw will rotate. If you
engage the half nuts then the dial will remain stopped.
When cutting a thread on the first pass engage the half nuts when the
dial is at a number against the line on the block, any number, but 1 is
the best. Do the pass, withdraw the tool and disengage the half nuts.
Return the saddle to the start position, doesn't have to be precise,
and adjust the tool for the next cut. With the lathe running the dial
will have been turning through all this. Here is the crunch. watch the
dial and as the number (eg "1") comes up against the line on the block
gently engage the half nuts, the dial should stop with the number at or
near the line on the dial block.
Using "1" as the number will work for all common (I repeat common, eg
UNC & UNF) threads. As you get more confident you start using other
number combinations on the dial appropriate to different thread pitches
(see the table on the change gear cover). This saves time as you can
engage the half nuts at say 3, 6, 9 & 12, ie you don't have to wait
for a full turn of the dial each cut. Once you get the hang of this
your confidence level will take a quantum leap.
Metric threads are somewhat more difficult to understand but there is
an excellent treatise in www.mini-lathe.org.uk; read it anyway it is
good stuff.
My morning coffee has finished so I had better get on with work.

One good turn deserves another.
Regards,
Ian


is--- In 7x12minilathe@..., "Ed" <edo@...> wrote: