Amateur with tenon threading question-

[Butch Lambert]

I do it a little different. I thread to the shoulder watching my Trav a Dial and then disengage the half nut. I then casually retract the cross slide. It leaves a thread relief that you can't see unless you look very close. Everybody has their own method and we do what we prefer. One of my buddies and a forum member made up a proximity sensor tied into his DRO and VFD on his old oriental lathe. When he gets to his programmed point on his DRO his VFD, with braking resistors, instantly stops the spindle. He retracts the spindle, does not disengage his half nuts and reverses the feed. Know you crank in your cross slide to "0" and crank in your compound and turn it on as the half nut is still engaged.

[Mram10]

I had NO idea a 3 phase had anything to do with finish on threads! I always touch mine with a thread file or emery cloth to pretty them up. Great info.

[sdean]

As with most all lathe operations the operator has the most influence on the results.

[Rubicon Prec.]

I don’t use a thread relief, but I do make a tool nose radius relief at the shoulder. This isn’t required if the lug opening or receiver face is chamfered sufficiently.
On integral lug receivers I thread at 750 rpm and pull out .005” before the edge of the insert crashes into the shoulder. With a separate lug, I thread one thread pitch under the lug.

[Pete Wass]

is my half nuts don't always engage totally so one can get "Chowered up" threads very easily. The gearing setup for me to cut the threads I need for tenons ends up giving me a fast feed rate and before one knows what they have, Chowdah! Perhaps there is a way to slow the feed rate down but I have yet to figure out how to do it and still know I'm cutting the thread pitch I need.

The only thing about the otherwise great lathe I bought is the danged change gears! Perhaps someone can help me out with slowing the feed rate down? I use HHS cutting tools for threading. My lathe doesn't have a conventional gear box on it. The lathe is a mid 90's Central Tool 13".

Thanks,

Pete

[killswitch505]

I had NO idea a 3 phase had anything to do with finish on threads! I always touch mine with a thread file or emery cloth to pretty them up. Great info.

It didn’t really make a lot of sense to me and I’m an electrician 😂 I’d think 1800 rpm is 1800 rpm but the more and more I researched it It’s fairly common with single phase equipment the sign wave on single phase is more spread out than 3 phase and guess that mean something. I can attest that the surface finish is much better now that I’m on 3 phase. If I were the one paying for all the up grades (motor, VFD and switching) I’d prolly have just lived with it.

[killswitch505]

I don’t use a thread relief, but I do make a tool nose radius relief at the shoulder. This isn’t required if the lug opening or receiver face is chamfered sufficiently.
On integral lug receivers I thread at 750 rpm and pull out .005” before the edge of the insert crashes into the shoulder. With a separate lug, I thread one thread pitch under the lug.

Are using CNC? Carriage stop? I’m pretty ing good like 200rmp with a tool width relief cut good I don’t even wanna think how fast that carriage is traveling at 750 RPM.

[Rubicon Prec.]

Are using CNC? Carriage stop? I’m pretty ing good like 200rmp with a tool width relief cut good I don’t even wanna think how fast that carriage is traveling at 750 RPM.

Yeah, CNC. I was threading tenons at 1100 rpm but for some reason one barrel manufacturer would chatter. Rather than changing the speed based on barrel maker, I just slowed them all down.

I’ve been wanting to video it but there isn’t much to see with the coolant spraying on the window.

[Richard]

I do it a little different. I thread to the shoulder watching my Trav a Dial and then disengage the half nut. I then casually retract the cross slide. It leaves a thread relief that you can't see unless you look very close. Everybody has their own method and we do what we prefer. One of my buddies and a forum member made up a proximity sensor tied into his DRO and VFD on his old oriental lathe. When he gets to his programmed point on his DRO his VFD, with braking resistors, instantly stops the spindle. He retracts the spindle, does not disengage his half nuts and reverses the feed. Know you crank in your cross slide to "0" and crank in your compound and turn it on as the half nut is still engaged.

a trav-a dial and have only seen one and never in use.
I know some thread straight in with the cross slide but I don't. Does the tool compensate for the movement of the compound? Or do you stay away from the shoulder to begin with?

Richard

[coontz74]

I was having a similar issues as you with a similar lathe. I know this may not be an issue your having but I’ll get to that..... I was having problems with my threads looking like . I did a ton of research and found that single phase lathes leave an awful finish on parts. I changed my belts that helped. I still wasn’t getting the finish I was seeing everyone else getting so I did a 3 phase upgrade using a vfd. Boom problem solved I could even go down to 1 RPM to thread if I wanted. I then tied the brake option to a micro switch now I can stop on a dime.

https://youtu.be/Ncc72aKgzVY

I would like to hear more about your “brake option and micro switch”. I have an Okuma LK with a metric lead screw and would like to use a setup similar to yours. Thank you.

[killswitch505]

I would like to hear more about your “brake option and micro switch”. I have an Okuma LK with a metric lead screw and would like to use a setup similar to yours. Thank you.

What would you like to know? I can post a parts list of what I used and take some better pictures and video tomorrow I’ll be chambering a 300NM for my father.

Drive
https://www.automationdirect.com/adc..._vac)/gs2-23p0

Brake resistor
https://www.automationdirect.com/adc...ors/gs-23p0-br

Limit switch
https://www.automationdirect.com/adc...racy)/cs067b-l

[coontz74]

What would you like to know? I can post a parts list of what I used and take some better pictures and video tomorrow I’ll be chambering a 300NM for my father.

Drive
https://www.automationdirect.com/adc..._vac)/gs2-23p0

Brake resistor
https://www.automationdirect.com/adc...ors/gs-23p0-br

Limit switch
https://www.automationdirect.com/adc...racy)/cs067b-l

That’s perfect!! Thanks!! If you could take a video and more pictures would also help. Thank you very much.

[Engrbill]

HERE IS THE EASY WAY TO TREAD TO THE TENON WITHOUT STRESS. i ADOPTED THIS WAY AND NEVER LOOKED BACK.
https://www.youtube.com/watch?v=Z-dqOi_z5bk[/url]

[coontz74]

HERE IS THE EASY WAY TO TREAD TO THE TENON WITHOUT STRESS. i ADOPTED THIS WAY AND NEVER LOOKED BACK.
https://www.youtube.com/watch?v=Z-dqOi_z5bk[/url]

I agree...that’s a very good way to thread worry free....but, my situation is trying to thread towards the chuck and having to keep the half nuts engaged.
I have a metric lead screw and am cutting regular threads with no factory brake, hence why I’m looking for braking ideas...or any ideas really...

I can cut some nice threads with one hand on the power lever and one on the cross slide wheel to keep carriage out of the chuck but it can be stressful at times...

Thanks for the link. Much appreciated.

[jackie schmidt]

HERE IS THE EASY WAY TO TREAD TO THE TENON WITHOUT STRESS. i ADOPTED THIS WAY AND NEVER LOOKED BACK.
https://www.youtube.com/watch?v=Z-dqOi_z5bk[/url]

I tried writing all that down, no luck. Can you give us the link to just touch?