Threading increments

[carlsbad]

1. I don't thread with the compound, I thread with the cross slide.
2. It depends on the setup and the material. In a stiff setup and cooperative material, I'll take a skim cut to check my setup, 2 large cuts, and a finish cut.
3. On stainless barrels, I take more passes but like Alex said, I thread at 300 rpm. usually I use .020 per pass until I'm near the end.
4. The exception is if the setup lends itself to chatter, then I'll have to slow down and take lighter passes.
5. Use a sharp tool.

 

[hogpatrol]

Different strokes, they all work. I use the compound 29 1/2, cutting on one side, chip rolls off like a curly fry. Depending on how rigid, a couple heavy cuts, maybe .060 on the first one, then lighter, 030s or .045s. Take it up to the last .005 or so and do a couple spring cuts for finish. I cut to the shoulder but on the Clausing I use, you have to be like Wilson in the movie Shane.

 

[ridgeway]

I have made threads many ways, but always infeed with compound. When I have a few thou left to take off to hit PD, I infeed straight in the x to clean up backside of the thread.

Thread however floats your boat. If it screws together and holds, you are good. If your first thread job is to attach a muzzle brake and she flys off when you fire, you gotta go back and figure it out, lol.

 

[hogpatrol]

. If your first thread job is to attach a muzzle brake and she flys off when you fire, you gotta go back and figure it out, lol.

 

[Dave in WI]

I guess I will have to try and take a little more on the beginning passes. I'm in the garage, got the tunes playin and am just enjoying myself. Real job is more hectic. this is relaxing. Plus, don't want to mess up a customers barrel.
Tarey

You get more "practice" your way....

 

[boltfluter]

You need a healthy cut on the first few passes. Light cuts generally will wear out a cutter just as fast as to heavy of a cut. My first cuts are .015 to .020 as there is very little tool pressure. Decrease as you get close to finish depth. A loaded tool is less likely to chatter as well. Many ways to do this job with good results. Carry on.

Paul

 

[Henryrifle]

Just to prove that I am a rookie, I set my compound to 29.5 degrees, infeed with the compound and follow the attached chart and as long as I don't screw up (see what I did there) it always turns out well. I thread at my lathe's slowest speed of 70 RPM using a A R Warner HSS threading tool and Viper's Venom cutting oil.

Henryrifle

 

[Lucky Shooter]

When you thread at these higher speeds, how do you time
the disengagement of the half-nut ?

If you use a relief cut, how wide ?

A. Weldy

 

[GenePoole]

I use a dial indicator clamped to the bed. Set it so that you get two full sweeps of the needle to zero, then disengage and retract. Take some practice. Do it with the tool removed a few times and practice getting the dial right on zero when the carriage stops. It helps that I have a giant dial on the cross-slide.

 

[GenePoole]

Took me awhile to find a picture with the aforementioned dial prominent. This is a South Bend 13 but was originally a turret lathe so I think that is why it has this huge crossfeed dial compared to other SB13s:

Notice the sharpie arrows on the dial. This is how I set it up for fast threading. The handle on the wheel is arranged so that I push it in the same direction (down) as the half-nut lever disengagement. The arrows ensure that I know which way the wheel is supposed to spin when retracting (this was apparently for internal threading). I keep one hand on each (the handwheel and the half-nut lever) then when the dial indicator approaches the mark, I push down with both hands. If all goes well, the dial indicator (not shown) will be on zero.

 

[Dusty Stevens]

Just do it enough. Dont use a pullout slot and dont rely on an indicator. If you use a pullout slot you gotta go too far to rechamber. Heres one in process. You can get even closer with a stand-up insert. The last passes go slower and get closer. Find a cutting oil that doesnt smoke too (tip of the day)

 

[PWS]

I do the same thing as Gene (‘cept go up to disengage the half nut and back out the cross-slide). I also try to set the handwheel so the crank is beyond vertical and on the same side as the required motion. That way, I don’t have to think about direction, just timing the up move on both. Learned that trick by having the crank at BDC and moving the cross-slide the wrong way once...

 

[Dusty Stevens]

I do the same thing as Gene (‘cept go up to disengage the half nut and back out the cross-slide). I also try to set the handwheel so the crank is beyond vertical and on the same side as the required motion. That way, I don’t have to think about direction, just timing the up move on both. Learned that trick by having the crank at BDC and moving the cross-slide the wrong way once...

I put my cross slide handle at about 10:30-11:00 and just give it a push. Was taught that on lesson one of threading which lesson 2 is find a method and never change

 

[Greg Y]

You can put your tool on the back side and thread away from the shoulder. Then the only thing you have to worry about is getting back to zeros and hitting the leadscrew on time.

 

[Dusty Stevens]

You can put your tool on the back side and thread away from the shoulder. Then the only thing you have to worry about is getting back to zeros and hitting the leadscrew on time.

I cant

 

[GenePoole]

I won't

 

[Dusty Stevens]

I won't

Talk about a crash with a threaded spindle

 

[hogpatrol]

Talk about a crash with a threaded spindle

On a Hardinge, better change that chuck dog direction too lest you have it in your lap.

 

[Lucky Shooter]

You guys are several classes ahead of me. I'm going to
remain a 70 rpm guy with an indicator and relief groove.

I can thread to a shoulder with an indicator and no relief
groove at 70 rpm but think its a risk for tool damage and
rework---at my skill level.

I set up an indicator and cut some air at 200 rpm and was not
consistent at a stopping point. Practice might improve this but
70 rpm will be the ticket for a while.

Ambition and imagination spark progress but reality must prevail
in the meanwhile.

Thank you guys for all the information.

A. Weldy

 

[ricco1949]

Engaging the half nut without a pucker factor for left to right threading by Joe Pie.