external threading away from headstock

[3strucking]

I want to purchase a tool holder for insert tooling so I can thread away from the headstock. What tool holder and insert do I need so I can get close to a shoulder and thread toward tailstock?

 

[epanzella]

To thread away from the headstock you have to run your spindle clockwise. This will require an inverted tool in front of the spindle, or an upright tool in the rear. You don't need special tools.

 

[darkzero]

For indexable tooling & if you want to start close to a shoulder & thread away from the chuck, because you are using the tool holder upside down, you should go with a LH tool.

 

[gi_984]

Check out Joe Piecynski on Youtube. A pro showing how it is done. A lot of good tips in his other videos also.

 

[3strucking]

I thought I would need a LH tool since I need to get close to a shoulder. Just wanted confirmation.

 

[darkzero]

I thought I would need a LH tool since I need to get close to a shoulder. Just wanted confirmation.

Yes, LH if you are using it upside down on a conventional manual lathe.

 

[mksj]

I would look at the Joe Piecynski on Youtube video carefully as to the type of thread holder and how it is flipped upside down. You will run into an issue with not having enough vertical adjustment for the holder, so in the video you will see he uses an adapter block and a separate screw mechanism to set the cutter tip height. One downside is you do not see what the cutting tip is doing, so a bit like flying on instruments only. I guess one could grind a HSS cutter specific to this application. In addition he only uses the cross slide to se the cutter depth, otherwise you will have some positional changes if you were to use the tool post slide.

Fortunately I am able to use an electronic stop and conventional threading, so all you need is to set the cutter ending position which can be withing 0.001" of the shoulder. I primarily use the cross slide for the thread cutter depth, but this depends on the pitch and the material. You do need to take slightly lighter cuts.

 

[HRgx]

Check out Joe Piecynski on Youtube. A pro showing how it is done. A lot of good tips in his other videos also.

There is a lot to be learned from Joe. I'm a subscriber to his channel.

 

[gi_984]

"thread holder and how it is flipped upside down. You will run into an issue with not having enough vertical adjustment for the holder, so in the video you will see he uses an adapter block and a separate screw mechanism to set the cutter tip height. One downside is you do not see what the cutting tip is doing, so a bit like flying on instruments only."

Agreed. I still prefer to have the tool right side up and see what I'm doing. But for some jobs it is the only way to get a good thread. For example I had to do a run of 36 round headed bolts with oversize shafts. Shafts were very short and about .255 in diameter. The ends of the shafts were to be threaded just enough to put on a 1/4-28 nut. No way to thread it conventionally or using a die without cutting into the short little stubby shaft. Flipped the threading tool upside down and feed to the tailstock. They came out great.

I've run the 15 inch Clausing colchester lathes in school. But they all had Dorian or Alorix CXA QCTPs. Never ran out of adjustment with those. In the video it looks like his are BXAs. So that might be why he had to shim it.

 

[mksj]

No way to thread it conventionally or using a die without cutting into the short little stubby shaft.

There is a way to use a die and cut a complete thread to the shoulder/fixed end point, I do this all the time for smaller threads. I cut the thread with a die the conventional direction to the shoulder, I then spin off the die and flip it and thread it onto the shaft cutting the final few threads to the shoulder or ending point with the full thread die end. You need to be careful not to over tighten the die against a shoulder or force it with the last thread. If cutting larger threads, then I also would cut away from the headstock if I did not have an electronic stop system.