Threading increments

[Lucky Shooter]

Question for you guys about threading.

How much do you advance the compound between passes ?

Thanks.

A. Weldy

 

[Devin Wiggett]

Depends on where you are in the process, I'll take a deeper cut at first, maybe .010 then down to as little as .002 as I get close to being finished. Not saying it's the correct way, but works for me.

 

[jackieschmidt]

It depends on the thread. We cut a lot of large threads, 5 inches+ on the diameter at 4 tpi, you can start with as much as .060 per cut untill you get 60 percent in, the gradually decrease to .005 toward the finish.

For typical threads found in gunsmith work, and with a dial that takes .002 off of the diameter per mark, I start with .030 from touch off, then .020 then .005 increments in from there. RPM is 230.

But as a note, I thread straight in with the cross slide, not at 29 degrees with the compound. It’s just a personal preference.

 

[Greg Y]

Zero. I run from the cross. The AR Warner tooling allows me a huge range of speeds with great finish. If I were under 12ish tpi, I'd work the compound and feed would depend on sfm and tooling choice.

 

[10XSHOOTER]

I thread upside down and reverse. I start at .005 until half way and then to .002 and finally at .001.
I thread straight in with the cross slide and 190 rpm. thread away from a shoulder

 

[rwk]

when u do enough u will get the feel for how much

 

[tobnpr]

Echoing "depends" on the thread pitch.
I'm surprised so many don't seem to use the compound.
To me, it makes the process a lot more "foolproof". Using the compound, all you need to do is return the cross to "0" and advance the compound whatever's needed.

If I were just using the cross, I'd need to remember the setting at each pass. No chance at all I wouldn't screw that up with "where was I ???".

 

[Lucky Shooter]

I started this thread because I know I've been too timid in advancing the compound. What surprised me was how many just go straight in without
the compound.

For whatever reason, I thought the use of the compound was pretty much the best way to go.

I threaded a test piece and started off with a couple of passes
at .015" on the dial and eventually, by cut and try, was able to
thread a BAT gage on.

I don't know if either method is better from a metal-cutting aspect
or if either is more idiot-proof but I can't see any difference in the
use of the threads.

The man lesson for me is that I can make larger increments and fewer passes.

This has been good for me----thank all of you.

A. Weldy

 

[skeeljc]

Threading in reverse with a LH tool mounted upside down has really made threading easy. I use only the cross slide and carbide inserts. 300 rpm is my max. Could thread at faster rpm but it is hard to hit the number when closing the half nuts.

 

[10XSHOOTER]

Threading in reverse with a LH tool mounted upside down has really made threading easy. I use only the cross slide and carbide inserts. 300 rpm is my max. Could thread at faster rpm but it is hard to hit the number when closing the half nuts.

I may have to look at speeding up the lathe. Have done 190 rpm for years. Carbide inserts here also.

 

[tobnpr]

For whatever reason, I thought the use of the compound was pretty much the best way to go.

Using the compound places most of the cutting force on the leading edge of the cutter.
Feeding straight in with the cross increases chip load and- with heavier pitches and deeper DOC- requires a heavier, more rigid machine.

Joe Pie explains it all...including computer rendering analysis.

 

[Greg Y]

Joe does a fantastic job of sharing his skills....this is a great one to throw in the quiver. Learning how to pick up a thread with an indicator will increase your quality of work.

 

[GNERGY]

I thread using the compound, about .003 at first till about half way then .001 till I'm finished. Use Warner HSS inserts and run about 100 RPM. Use Vipers Venom lube.
Tarey

 

[dnellans]

I thread using the compound, about .003 at first till about half way then .001 till I'm finished. Use Warner HSS inserts and run about 100 RPM. Use Vipers Venom lube.
Tarey

Holy crap that’s little bites.

If I was doing a 1 1/16 18TPI barrel tenon I’m going to typically need to get to .043 on the compound before I would even consider test fitting (with current tool and height Ive got).

I typically will do a scratch pass to check, then (on compound dial) .010, .020, .028, .035, .040, .042, .043. 7 passes before first test fit where i’d expect it to start threading and not get 1/4 of way on.

your method of .003 bites would be 7 passes just to get to .021 and then another 22 passes to get to .043!

that blows my mind

 

[tobnpr]

Dayum....
Can't even get a chip at .001, it's dust...
Guess when you're not doing it for profit you can "afford" to take all day threading a tube if it floats yer boat.

I'll go 5 or 6 on fine (24-32) pitches for muzzle threads. 8 or 10 on coarser threads.
Now, this is barrel threads- and I keep it light because the setup is comparatively light.

If I'm threading something else rigidly held in the chuck or collet, I'll rip blue chips off the m'fer.

 

[Alex Wheeler]

You can peel what ever you like so long as the last few passes are light enough to get the finish you want. As expensive as carbide is, I feel out what makes it last as long as possible. Sometimes a heavy pass at the lower speeds we run can really shorten the life of the insert. If you are concerned about how long it takes, speed up the rpm, I usually thread at 260-375, not only will the finish benefit but you wont mind a few more passes.

 

[Greg Y]

The hss inserts are awesome for slower work.

 

[tobnpr]

I usually thread at 260-375

If I did that...

C R A S H

 

[therifler]

i've been machining for 52 years . but i have only been threading with the cross slide for about 49 years never gave it a thought about the tool load to be honest . sounds logical certainly has merit .

 

[GNERGY]

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