[HorridHenry]

We all know that its a pain to use this threading scenario when we need to engage the half nuts in exactly the same number on the dial for each turn.

I cannot get my head round this as to why it cannot be simpler?

I mean what about setting up the tool about a 16th of an inch away from the job end and putting a temporary locking block on the bed way/s at the side of the saddle ie butt up against it and then start the lathe and engage the half nuts,once its made a first cut stop the auto feed and machine then withdraw the saddle back to the temporary stop and reapeat the procedure again and again ti we have our screw thread.

I mean the only thing that governs this is the type of thread and pitch from the gears change.

Will this work? cos I'm gonna give it a go tomorrow to satisfy my curiosity.

[hoss2006]

A floating threading tool is another idea to use when reversing, no need to back off the handles.
Here's an example.
Hoss

[ame=http://www.youtube.com/watch?v=8JFdNaBD5GM&feature=my_favorites&list=FLjo RKEpk7uE5Wzf4b-IFTFg]threading 2.AVI - YouTube[/ame]

[txcncman]

People have been threading on manual lathes for about 100 years. Don't you think if there was a "better" way to do it, that someone else would not have already thought of it and it would be standard practice by now? Go ahead and try your experiment and post your results back here. Please include the time savings.

[underthetire]

There is a better way, it's called a cnc

[bigspike]

Where can that floating holder be found?

[bigspike]

Well it only took 7 hours of searching the net, but I finally answered my own question.

For those who are having trouble cutting threads because their lathe does not have a threading dial, cross slide backlash or slop, and / or all of the above or some other reason, I will provide the answer.

No one makes this tool holder. You must make your own.

I found a forum posting that details a very good design on MadModder.net in the Project Logs forum. Swingup external threading tool Lots of pictures and very detailed explanation and discussion.

For my needs, I will modify a quick change tool holder that I have instead of making one from scratch. I plan to:

• Make a filler block for the groove that normally holds the tool bit.
• Mount a bearing block to the side of the holder aligned with it's top surface even with the bottom of the groove to support the tool bit. Two dowels and a bolt will connect this to the quick change holder.
• Since I use index tool holders, I will modify the 60 degree bit to pivot by milling the side of the end 1/4" deep x 1/2" wide
• Mill a corresponding L shape block to "ship lap" to this end, projecting down .44" x 1/2" wide and across underneath to the quick change holder. This will be bolted to the holder with a shoulder bolt as a pivot. And be connected to the tool bit with a press fit dowel. This dowel will stick out about 3/8" to allow it to be used as a handle for very deep threads that might catch on reversing.

The attached image shows the basic design, the tilt up concept and the two circles simulate the outer diameter and a thread depth cut.

[packrat]

Why not back out the cross-feed like they've done for ever?

[bigspike]

When I back out my cross slide, the scale dial shifts. There is no accuracy. I have dismantled it and most of the problem is poor quality Chinese workmanship. My lathe had a pealing sticker for a zero mark. A poor quality casting. And a lead screw nut that is pretty badly made.

Until I can replace/rebuild all these issues, the modification of a swingup tool holder will solve these issues.

[DMF_TomB]

When I back out my cross slide, the scale dial shifts. There is no accuracy. I have dismantled it and most of the problem is poor quality Chinese workmanship. My lathe had a pealing sticker for a zero mark. A poor quality casting. And a lead screw nut that is pretty badly made.

Until I can replace/rebuild all these issues, the modification of a swingup tool holder will solve these issues.

.
if your cross slide dial shifts (and you do not want to fix it) , use a dial indicator and magnetic base and indicate tool holder with magnet stuck to lathe carriage. where no good spot for magnet you might drill and tap a 1/4-20 hole and unscrew rod from magnetic base assuming you have rod with 1/4-20 thread screwing it to magnetic base.
........ personally using thread dial is simple and works, if confused about which number to use always use the same one.

[earthman]

Interesting thread this is, I've not even attempted to use my lathe for this.