What Lathe do you use for makin threads?

[Swede44mag]

I have a Atlas lathe that is as old as me it works fine for turning the outside of parts but it won't make threads worth a darn. Without getting to expensive what kind would make good threads?

[wonderwolf]

What is it doing that isn't allowing it to make threads right? auto feed gearing messed up? I have a old South Bend and it just took a lot of learning and understanding in order to do threads. Its just like a rifle in that very rarely is it the machine that is at fault.

[Arnie]

I have a 9 inch South Bend also .It didnt have a quick change box or a thread dial so i reversed the motor with out releasing the half nut lever and that worked fine till i found a quick change box and made a thread dial. Im sure any of the new Asian made lathes would work ok for you . Arnie

[Buckshot]

I have a Atlas lathe that is as old as me it works fine for turning the outside of parts but it won't make threads worth a darn. Without getting to expensive what kind would make good threads?

..........Even a lathe with a badly worn leade screw should still make good threads, as even a worn lead screw still has the correct pitch. There must be some other problem, because if your setup is correct (tool, angle, setup, thread dial) your threads should be good. What's happening that shouldn't be happening?

.............Buckshot

[Swede44mag]

When I try to lock in the threading dial sometimes it will not lock in on the wright mark and will screw up all my threads by cutting inbetween them. I learned to cut threads at a Votec machine shop class on a lot better lathe. I think it was a clausing.

What type of lathe do you use to cut threads that is not an antique like I have and is not several thousand dollars?

[Buckshot]

When I try to lock in the threading dial sometimes it will not lock in on the wright mark and will screw up all my threads by cutting inbetween them. I learned to cut threads at a Votec machine shop class on a lot better lathe. I think it was a clausing.

What type of lathe do you use to cut threads that is not an antique like I have and is not several thousand dollars?

............I have a 11" Logan (actually made by Powermatic in 1981).

When I try to lock in the threading dial ............

You mean when you try to lock in the half nuts? The thread dial just tells you 'When' to engage the half nuts. As I mentioned, even if the leade screw's threads are worn to a spiral nub, the correct pitch remains, and it will cut correct threads. You're cutting from right to left, and starting with the tool just off the right end, correct? I don't know what TPI you're wanting to cut, but as a test if you engage the half nuts at the same number on the dial it obviously HAS to track as before.

Since the half nuts are being used ot propel the carriage the only way it could mess up like that (cutting on the crests or flanks of already laid down threads) is if the half nuts skip. In that case the carriage would of course hesitate until they bit again and the tool would mess up the threads in that spot, since the work would continue to turn while the tool was stationary. Have you tried threading and keeping thumb pressure down on the half nut lever?

You can cut threads on any lathe with a leade screw and half nuts to move the carriage, whether it has a QC box or change gears. Used lathes are where you find them. I paid $1500 for mine.

http://www.fototime.com/D6F506031937D20/standard.jpg

It came with a lever actuated 5C collet closer, L00 spindle nose, a 6 Jaw Buck Set-Tru, a 2 jaw Buck Set-tru, a 8" Rohm 3 jaw chuck, and a bed mounted turret tailstock for $1500. Gopherslayer just moved and sold his older 11" Logan with 5C setup, collets by 64ths, bed mounted turret tailstock, KDK toolholders, and a pickup truck load of spare tooling and chucks, plus a 8x32 Millrite turret mill and tooling for $2200 !!!!!!!!!!!!! Don't know where you live, but keep your eyes open and your ears to the ground, let your freinds know you're looking and who knows what may pop up?

BTW, if you do happen to find a 10" or 11" Logan and it's a change gear machine, I have a spare QC box for sale :-)

.............Buckshot

[7of7]

When I try to lock in the threading dial sometimes it will not lock in on the wright mark and will screw up all my threads by cutting inbetween them. I learned to cut threads at a Votec machine shop class on a lot better lathe. I think it was a clausing.

What type of lathe do you use to cut threads that is not an antique like I have and is not several thousand dollars?

I had an old Atlas.. the threading dial could be disengaged. I engaged it and tightened it so it wouldn't disengage. The dial should not be disengaged from the lead screw while threading at all. (hense the reason why I just tightened it down while engaged.)

[akajun]

Is this a 6" atlas by chance. I had one that had a severly worn spot on the leadscrew. The halfnuts would still engage it but the dial would easly skip when the leadscrew flexed. Good news is that clausing still has leadscrews for $180.

If thats not it, check your gearing setups, maybe have the wrong gearing.

[frnkeore]

The way that the chasing dial works is this....... you may engage the half nuts on any line for even threads but for odd threads you engage on any numbered line. Check the engagement of the chasing dials gear (bottom of dial) into the lead screw, if not fully engaged it can slip on the lead screw. Make sure that the chasing dial is for your lathe or at least that it's for the right pitch lead screw.

Frank

[daschnoz]

Does your lathe have a reverse gear? Back your tool bit off the material and, with the feed still engaged, run the machine in reverse to get your carriage back to the right. Reset your dials, switch to forward, and make the next pass.

Make sure you have enough thread relief at the end of the cut to allow the tool bit ample travel while the spindle comes to a stop.

This method takes a bit more time, but it's sure faster (and cheaper) than making your piece over again.

[Casting Timmy]

Other things to watch for when cutting threads:
Not all compunds have the 0 degree mark in the same location, I know mine is 90 off from most. (Check by having compund so it points straight in and then turn about a 1/3 of 90 degrees to the left. Then set to 30 or 60 degrees as appropriate.)

If your tool height is a little too high, it will cut at first and then it will stop cutting as the tool height is too high. Then after a few cuts the next cut will grab the tool and take too much of a cut and ruin the threads. (You'll know as it will be making threads and then it won't take hardly anything off for a few passes. I always had a tough time with the lantern tool post holder.)

If you're grinding your own bits and just starting out, see if you can get someone to grind a bit for you.

Make sure you engage the half nuts and not a power feed lever. A guy I know has both a half nuts lever for threading and a powerfeed lever which reduces the speed even more. It took him a while to remember he was using the wrong lever and that's why his tpi was off.

I would really check your bit height first, I know that was my real problem in the beginning. I love my old lathe and now have a tool block for my bits, but those quick change set ups really make tool height adjustment a lot esaier. I'll have to get one of those set ups after a bit.

[MBTcustom]

Back your tool bit off the material and, with the feed still engaged, run the machine in reverse to get your carriage back to the right. Reset your dials, switch to forward, and make the next pass.
This is how I thread also. I got in the habit of leaving the half-nut engaged because on old worn out lathes, sometimes the nut never goes in the same way twice, and while you do get working threads, they look pretty rough. By leaving the half-nut locked and using the reverse function to move the tool back to home, you can make clean looking threads, even if you are using a ***.
If I am threading to a shoulder, I stop the lathe before it gets there, pop it into neutral, and spin the chuck by hand until I get to the exact spot I am shooting for.
I dont see why it matters, but my lathe is a 17" LeBlond with 8 foot ways.

http://castboolits.gunloads.com/imagehosting/thum_177714de3c09aaec8e.jpg (http://castboolits.gunloads.com/vbimghost.php?do=displayimg&imgid=1023)

A little big, but it sure cuts nice and I can engage the levers with one finger. Its a 1950-something model, right before CNC came on the scene. In my opinion, finding one of these in good condition is hard to do, but if you get one you will understand that American machinery used to be the best.....bar none. It doesn't just get the job done, It works with you and was designed to be easily manipulated by skilled craftsmen. I love it.

[uscra112]

If you're grinding your own bits and just starting out, see if you can get someone to grind a bit for you.

Pre-ground 60 degree tools are so cheap now it's hardly worth the effort to grind yer own. Literally a coupla bucks a piece, even at MSC. Granted, knowing how to grind the angles on a lathe tool is nice to know, but unless the SHTF and we can't buy them anymore.... well, you get the idea.

BTW my lathe is an ancient South Bend toolroom lathe with the big hole and plain bearing headstock. Plain bearings properly set up always gave me better surface finish with less trouble. Even my old Monarch 10EE wouldn't do what my S.B. can in that dept.

[Safeshot]

Old Craftsman 12 inch (with quick change gear box and back gears). Cuts threads well, go slow in back gear mode and use light cuts, cutting oil and keep chips clear. Feed with tool post feed set at 28 to 29 degrees for 60 degree threads. Start cutting thread with cross feed dial (at "register") set on "0". Advance cutting tool (initial cut and each progressive deeper cut) with tool post feed, Back tool out of cut with cross feed, reposition to start of threads, bring cutter back to "register" with cross feed. Finish with very very light "scraping cuts" with cross feed. I always engage "feed" (half nuts) on number "1" on indicator (just out of habit). It is slow, but quicker than "do overs". Just my opinion. Safeshot

[rbertalotto]

Jet 12X36 BD.........converted to DC motor and Shooting Star DRO installed. EXCELLENT gunsmith lathe!

http://images50.fotki.com/v1530/photos/3/36012/5991434/P1020392-vi.jpg

http://images9.fotki.com/v1543/photos/3/36012/5991434/P1020393-vi.jpg