G9729 Left Hand Thread Cutting

That will be an interesting way of doing it. Please let us know how it works.
 
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Digital ratation counter in manual mode for different threads and then mark those speeds on the dial indicator of the new motor controller.
Not good enough. For a given TPI the ratio of the spindle speed to that of the leadscrew must be *exactly* equal to the ratio of two particular integers. This can be done with electronics but it can't be done by manually setting a speed control.
 
Come to think of it your probably right! Once the motor starts to load down the rpm's will drop and change the cut. Well maybe it's time to go back to the drawing board ! An adjustable idler gear to reverse the lead screw is about the only way to go.
 
WOW! He's what I'd have to call a "Master Machinist!"
 
This works. Now all I have to do is figure out a slider rail/bracket to mount the gear. Two thumb screws to replace the allen head screw will need to be added for ease of doing the change. Also the rail/bracket can't block gear change procedure for different gear changes. Gotta think this one out.

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Digital ratation counter in manual mode for different threads and then mark those speeds on the dial indicator of the new motor controller.
To make threads you need to make multiple passes, backing out and backing up after each pass. The next pass has to be lined up exactly in the cut of the previous pass. I don't understand how that can be accomplished without a mechanical link between the spindle and the leadscrew. I've seen electric powered feeds before but they only worked for turning, not threading.
 
Take the lead screw out of gear (neutral), hand crank back to correct dial number and then re-engage lead screw.
 
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You're still relying on an electric motor to traverse the carriage EXACTLY in the previous cut with varying loads like DOC changes. It would be interesting to see if it's possible.
 
But remember in #14 above I scraped that motor idea and went back to the idler gear as pictured above.

Going to mount the idler gear from the bottom cause it will be easier to mount the slider bracket.
 
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