I needed to learn more about using my lathe, so I decided to learn how to cut .595-32 NS 3-A threads. This is used on M14 barrels for the castle nut. 32 threads per inch. I had about five failed attempts but finally succeeded. Standard 24 TPI should be no problem now.

I have plenty of scrap barrels, so this was good fodder for learning.









Tony.

Looks good, congratulations.

There is a guy on Youtube I watch who is in Australia. He has a one man machine shop and does some amazing work.
I watched him machine threads using a lath and could not figure out how he cuts threads multiple times on the same piece and does not mess up.

Love it! Its called single pointing. I even learned to grind new tools from HS steel blanks. Gotta tell about my screw up back in Machine Trades School. Leblond lathe with a collet closer. A part I was making to print had a bunch of features, one of which was a external thread. For some strange reason, I took the nearly threaded and completed piece out of the collet to observe. I needed a bit more thread depth so back in the collet she goes. Bumped the top slide a bit and engaged the power feed. My beautiful threads cut off there so pretty blue and hot.. It was a performance test to be graded so I had time to make another.

Awesome - well done.


I’ll never forget when I needed a 1” shaft threaded to hold the weapon on the Battlebot…

Went to a speed shop where the hillbilly dirt-tracker dude just walked over to a drill press and threaded the thing by hand using his palm as the friction… took less than 15 seconds. He grinned widely at me.

Power move, super flex on machining/theading chops.

Cool stuff! Love the knurling.

Last week I got a quick lesson in, "it's been forever since I used a lathe." I can get around the old Bridgeport fairly well, but my lathe skills suck.

We had a technician in late one evening and he needed an alignment pin for a machine setup. I talked to one of the shop guys on the phone (looking for the pin in his toolbox) and he said, "well, heck, if you can't find it just make one."

I stared at the old Sharp for longer than I want to admit before I remembered how to change a collet. But I got the part made! Its surface finish isn't something to be proud of, but it did the job.

After so many years of just acknowledging that my lathe skills are bad, now I'm wanting to get back into it and re-learn.

Good looking thread. If I recall, 3-A is a tight, smooth external thread? As tight and smooth as possible, something like the smoothness found on a micrometer. Nicely done.

quote:

Originally posted by 71 TRUCK:
Looks good, congratulations.

There is a guy on Youtube I watch who is in Australia. He has a one man machine shop and does some amazing work.
I watched him machine threads using a lath and could not figure out how he cuts threads multiple times on the same piece and does not mess up.

Lathes set up for thread cutting allow you to re-position the tool post to the exact same starting point so multiple passes are actually pretty easy.

quote:

Originally posted by 71 TRUCK:
Looks good, congratulations.

There is a guy on Youtube I watch who is in Australia. He has a one man machine shop and does some amazing work.
I watched him machine threads using a lath and could not figure out how he cuts threads multiple times on the same piece and does not mess up.

There is a threaded rod that runs the tool carriage at the desired thread per inch , the operator cycles it on and off engaging/disengaging the drive screw…

It’s cool, you should go watch a machinist work

quote:

Originally posted by Chris42:
Good looking thread. If I recall, 3-A is a tight, smooth external thread? As tight and smooth as possible, something like the smoothness found on a micrometer. Nicely done.

Yes, it's a very fine thread. Here's a picture with a 1/4-20 screw for scale. The triangle is what I used to guide me as I ground the angles on the HSS blank on the disk sander. The fish tail is used to check for the correct 60˚ angle. My iPhone has some nice macro lenses, so the thread is hard to put into perspective when it's zoomed so close.



Tony.