The Home Machinist!

...and the challenges continue.

I'm trying to cut a 13 TPI...
What number on the indicator do I need to use?

Behold my stumbling block!

I set it on 1 just to see and it worked, so now I know. Should I assume it's a 1 anytime is not listed in the chart?

TechTony wrote: All is working well now.

Hurray! Have fun!

TechTony wrote:I set it on 1 just to see and it worked, so now I know. Should I assume it's a 1 anytime is not listed in the chart?

20161101_204127.jpg

Ok, if I recall correctly, you can engage the half nut on any number if the thread pitch is a) inch and b) divisible by 3 (eg: 6tpi, 9tpi, 18tpi, 24tpi, 27tpi, etc.) You can engage on either 1 or 4 for other inch thread pitches. Finally, you cannot use the thread dial at all for metric threads.

For metric threads you have to stop the motor, back the tool out of the cut, reverse the motor until the tool has cleared the start of the thread, stop the motor, reset the tool, set the motor in forward and start the next pass, leaving the half nut engaged at all times until the thread is complete.

that's concerning (about the metric threads)..... since I really like running my threads with the motor in reverse and the tooling mounted upside-down..... guess i won't be doing too many metric threads.... hopefully....

TechTony wrote:that's concerning (about the metric threads)..... since I really like running my threads with the motor in reverse and the tooling mounted upside-down..... guess i won't be doing too many metric threads.... hopefully....

Ok. So do the same thing except wind the tool post away from you and put the motor in forward to the left side of the thread then. It doesn't really matter, so long as you do not disengage the half nut from the leadscrew until the thread is completely finished.

Keep in mind that when you are threading, the thread dial WILL NOT TURN.

That is normal.

The carriage movement and the speed of the leadscrew exactly offset each other.

You will see it turning if you move the carriage manually, and it will turn when the leadscrew is turning but the halfnuts are not engaged.

If you don't know how to use the thread dial, google for a pdf of the book "how to run a lathe" by South Bend. There are older out-of-copyright versions available on the web, and how to use a threading dial probably hasn't changed since the Cubs won the world series.

Oh, yea, they just did.

Since the PRIOR time the Cubs won the world series.

Steve

Last post of page 1 of this thread.... got the dial rotation issue figured out. The hole wasn't machined out enough to allow the thing to rotate, so I fixed it. It was practically press fit into that block. Works as it should now. Thanks though.