On 2011-12-24, wrote:
On 24 Dec 2011 03:14:39 GMT, "DoN. Nichols"
wrote:

On 2011-12-23, wrote:
On 21 Dec 2011 03:53:33 GMT, "DoN. Nichols"
wrote:

[ ... ]

I do have a threading indicator but a cursory inspection would suggest
that it is not working. In any case I felt I wanted to take that
variable out of the equation for the moment. If I do more of this I
shall re-visit it.

[ ... ]

I do not think it turns at all. Pending detailed assessment.

You snipped out the part where I mentioned that it could be
mounted but disengaged, and was likely shipped set that way to reduce
wear on the leadscrew until you are ready to do single-point threading.

Is yours held to the side of the apron by a single screw? If
you loosen the screw, can it be rotated so the gear on the bottom end
engages the leadscrew? That should be all that is needed to make it
work.

It is both of those but will not turn.

When backed away from the leadscrew, will the gear at the bottom
turn by hand? If it is frozen, there is something too tight in the
threading dial assembly, and that needs to be disassembled to find out
why it is frozen.

If it does turn, rotate it back into contact with the leadscrew
(working the carriage back and forth a little until the gear lines up
with the threads of the leadscrew and drops into engagement).

Once that is done, with no half-nuts or longitudinal feed (if
the latter is separate from the half-nuts) engagement, crank the
carriage back and forth. The dial should turn. If it does not, look at
the gear on the bottom and verify that it is turning (you should not be
able to move the carriage otherwise given the conditions I have
described.)

If the gear turns and the dial does not -- check that the screw
in the center of the dial is firmly tightened. (Assuming that it is
held on by a screw through the center as in the photo on the website you
posted a while back in this thread.

It is possible that the dial is a permanent part of a shaft, and
there is a setscrew or a pin connecting the dial to the gear. Mine is
of the latter design. Make sure that those are in place and tight as
well.

Once all of this is verified, with the threading dial pickup
gear enaged with the leadscrew, you should observe the following
conditions:

1) With the half nut (and possible feed lever) disengaged, the
spindle not turning, and the carriage cranked left to right, the
dial should turn as the carriage moves.

2) With the half nut (and possible feed lever) disengaged so the
carriage is stationary, the spindle turning, and the
reverse/neutral/forward lever on the gear train to the leadscrew
in either left-hand (reverse) or right-hand (forward) (as when
you are threading) so the leadscrew is turning, the threading
dial should turn fairly slowly (unless you are set up for a
fairly coarse thread, which would cause it to turn faster).

3) With the half nut engaged (as for threading) and the spindle
turning, the dial should appear stationary, but the carriage
should be moving. (Probably a good idea to set up for a very
fine thread while doing this test, to avoid running out of
carriage travel while you are looking at what is happening. :-)

The threading dial shows the position of the carriage with
relation to the leadscrew, to show you when to close the half nuts (with
the spindle running) to track the same path as before. While waiting
for the right number to come up, you can sometimes crank the carriage
backwards to get closer to the number you want to close the half nuts
at. This won't get you started cutting the threads any sooner, but you
will be watching the carriage move towards the start of the workpiece,
instead of sitting there anxious, waiting for the number to finally
reach the right point to close the half-nuts. (This is also the reason
that there are multiple numbers and index lines on the dial, so you can
(when the threads are right) close without waiting for a nearly full
rotation of the threading dial.

You really *should* take the time to make sure that the
threading dial works properly on your lathe -- it is a great time saver,
so any time invested in making it work right now will be repaid many
times over the life of the lathe.

Enjoy,
DoN.

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