G9729 Left Hand Thread Cutting

[LX Kid]

Doesn't seem to be that many people who have bought these machines. Maybe that's some handwriting on the wall that I should have read somewhere. I bought my Grizz G9729 beginning of last summer and have only been able to do anything with it in the last 30 days. The heat, here in Florida, just kept me out of the shop. Anyway after a "lot" of modding and repairs I have it online to make some chips. My biggest problem was the pivot gear was squeezing the rack gear. I had to do some shimming of the cross-slide gear box to make it usable.

Now after rambling, has anyone made a reverse tumbler for their lathe? These lathes have been around for long time and only thing I see is DC motor drive mods attached to the lead screw. I would prefer a mechanical idler gear to enable reversing the lead screw. Anyone know? I do have a treadmill torn down, and ready to do mod, but have but have been reluctant.

 

[pdentrem]

The late Steve Bedair added a tumbler gear to his 9x20 lathe. Check out his write up and MORE on his site. It will likely give you some ideas to fit your lathe.
Pierre

 

[LX Kid]

I had no idea that Steve Bedair had passed away. I had visited his site many time in past years when I had my 9x20 lathe. He and his talent will be missed by all. Thanks

Is it possible to turn the cutter upside down and run the lead screw in reverse to cut left hand threads?

 

[pdentrem]

No. The cutter has to be ground properly as the angles will be on opposite sides. Use the tool in standard position with the leadscrew in reverse.
Pierre

 

[LX Kid]

There is no reversing the lead screw without reversing direction of chuck. That's why I want to mod the lead screw direction in relation to forward turning of the chuck.

 

[LX Kid]

Think I'll keep my original idea of making the a variable speed lathe, with the treadmill stuff and just add another motor for the variable reversing of the lead screw. On a variable speed feeding lead screw experimentation would have to be done to get the feed proper for different thread spacing. I'd think a 1/5hp dc motor would do the job for lead screw.

 

[pdentrem]

Exactly, the tumbler reverse solves all the problems. Can you put an idler in the gear train to reverse the lead screw? You just need a single gear to do the job.

 

[LX Kid]

The way the the gears are set up makes it a little different than Steve Adairs' 9x20 lathe.

 

[epanzella]

Think I'll keep my original idea of making the a variable speed lathe, with the treadmill stuff and just add another motor for the variable reversing of the lead screw. On a variable speed feeding lead screw experimentation would have to be done to get the feed proper for different thread spacing. I'd think a 1/5hp dc motor would do the job for lead screw.

If I understand you correctly you're gonna have one motor run the spindle and another run the lead screw? If the lead screw is not indexed to the spindle I don't see how you'll cut left hand threads or any other kind of threads.

 

[LX Kid]

Digital ratation counter in manual mode for different threads and then mark those speeds on the dial indicator of the new motor controller.