Day 1 Practice - lessons learned. 12/30 update

[Stan Taylor]

This was cut with Warner HSS threading tool on my South Bend Heavy 10 lathe! Rem 700 16 TPI chambered in 20 Vartarg

Sweet looking threads.

 

[Danny1788]

Thanks Gene. Frick! I have been using any number on there since it is 16 tpi, but I think I’ll try one while hitting the same number every time. Could the threads look like that by having slop in any handles? Is the cross slide easier to make nice threads? Is tooling playing a part, or is this mainly me? I keep the machin running the entire time, engaging and disengaging the half nut. Honesty appreciated

That handle never left my hand!

Even if the thread pitch can be cut on any number, I just always use the same number and wait for it to come back around. This is how I do it so I know I'm catching the barrel at the same exact point in reference to the lead screw every time. Also after seeing your other posts your last threads are looking better. But just wait for the correct threading tools to come in, I only use ARW HSS tooling and solid carbide micro100 boring bars

 

[hoz53]

Usually pretty slow. It ain't a race. 150 or less. At slow speeds, carbide, like anything else, likes to be submerged in good cutting oil. Also, going too fast while threading makes you susceptible to chatter on the final passes when you are taking a wide light cut. --Jerry

ok thanks

 

[mram10]

I don’t respond to all, but I am definitely listening and learning from you all. I’ll post more pics this week when I get my tooling. My screw post for my qctp is too small and I need to machine another. I realized it was moving slightly. I will also grind a good threading tool to give it a try.

 

[mram10]

Day 3.
Decided to grind one of my hss 5/8 into a 60deg thread tool. I didn’t sharpen it very well. Ran it at 90 rpm. Made sure to end going into the piece. Tried 3-5 thou each pass to see what it liked. Half way through it jumped the threads. Guessing it is that darn tool post mount. Next job is to make one of those....after I sharpen and shape my cutting and threading hss bits.

 

[Stan Taylor]

View attachment 1029941 View attachment 1029942 Day 3.
Decided to grind one of my hss 5/8 into a 60deg thread tool. I didn’t sharpen it very well. Ran it at 90 rpm. Made sure to end going into the piece. Tried 3-5 thou each pass to see what it liked. Half way through it jumped the threads. Guessing it is that darn tool post mount. Next job is to make one of those....after I sharpen and shape my cutting and threading hss bits.

You are getting there mram just be patient it looks like it slipped or something you should know better than anyone what happened you were there you'll get it perseverance pays off

 

[carlsbad]

He's getting there but having more problem's that I would have anticipated. something isn't repeating or something is moving in his setup. Hard to diagnose from afar.

Mram, take a day off and watch youtube videos. I recommend abom79, tubalcain, and joe pieczynski. These guys are fun to watch and maybe you'll see something in their setup that you don't see in yours. Abom is a 3rd generation pro who lets you watch him doing real jobs and he's a very likable guy.

Merry Christmas,

Jerry

 

[ridgeway]

Take a pic of the tool you ground.

5/8" blanks? That's pretty big to grind and learn from. Get some 1/4" or 5/16 to work with to make life easier...

Pick up a Machinery's Handbook to read in your spare time.

 

[TRA]

How used is this lathe? Looks like you have issues with the lead screw and or possibly the half nuts are worn out. Could have cross slide and compound issues.

You are wasting your time attempting to practice cutting threads without properly adjusted equipment or one with worn out parts. Get a good, properly sharpened tool. Without that and making sure your lathe is not part of the problem, you are just wasting your time. You can buy a cheap brazed carbide already ground to cut threads. At least if nothing else it would provide you with an example as how your ground bit should be ground. Grinding a threading tool takes more savvy, than actually cutting the threads, I doubt you are going to be proficient enough to grind that tool, any time soon. You can watch videos till hell freezes over, but unless you have the proper tools and tooling properly set up, and a machine in good enough condition to cut acceptable quality threads, you are not going to achieve much better threads than you have now.

What ever is causing your issues now will likely break your tooling. Threading tooling is fragile and any very susceptible damage due to operator and machine issues. Once you chip the point of the tool, it's junk.

 

[shortgrass]

Your quick change tool post is new? Most all that I have seen for small lathes like your 12" have the "T" nut too tall, it sticks up above the compound slide,,, and the tool post should be against the slide, not the "T" nut. The "T" nut supplied is over-sized in every dimension, so they can be fit to most any "T" slot.

 

[carlsbad]

Your quick change tool post is new? Most all that I have seen for small lathes like your 12" have the "T" nut too tall, it sticks up above the compound slide,,, and the tool post should be against the slide, not the "T" nut. The "T" nut supplied is over-sized in every dimension, so they can be fit to most any "T" slot.

Excellent suggestion.

 

[mram10]

The main issue I found is the qctp mounting bolt has a lot of slop diameter wise. It hasnt been locking in place due to some mods I had to make. It has been shifting a bit, I found out this morning. The next project after making some good tools is making a good post bolt thingy. Also, I was taking too big of bites near the end of the threading. The half nut engagement was me on the jump, I think. I remember one that i wasn’t sure it engaged. That might have been it.
The lathe is a new eisen 12x36gh. I leveled it and ran the aluminum cylinder test and adjusted after.

 

[shortgrass]

Excellent suggestion.

I have learned a little bit in 42yrs of machine shop experience...... When you tighten the center bolt, if it draws the "T" nut up against the bottom of the tool post instead of drawing it up against the top of the "T" in the slot, it is not securing the post as it should. Don't know about your bolt diameter thing, shouldn't be an issue. Shear friction created when you tighten the nut on top of the tool post against the slide should be enough for what you are doing. I drill 1 5/8-1 3/4 in 4130 bar off the tool post all the time,,, on a 20" swing lathe, that is..........

 

[carlsbad]

Shortgrass. I saw this on a new bxa holder 15 years ago. 5 minutes in the bridgeport fixed it so it wasn't very memorable. Not sure if mram10 has a mill yet. He can do it with the 4 jaw in the lathe. --Jerry

 

[shortgrass]

Shortgrass. I saw this on a new bxa holder 15 years ago. 5 minutes in the bridgeport fixed it so it wasn't very memorable. Not sure if mram10 has a mill yet. He can do it with the 4 jaw in the lathe. --Jerry

Or a mill file if it's not too much to take off, or even if it is! If the "T" nut is the problem it has to be fixed before continuing. It a minimum needs to be checked. The tools must be secure in all connections to the slide, or you are inviting a potential disaster. few understand the forces involved with cutting tools and steel. I wouldn't want to 'wear' that tool post any more than I'd want to 'wear' a chuck key.

 

[shortgrass]

I think facing it in a 4 jaw is a bit 'advanced' for him at this stage of the game.

 

[GenePoole]

Cheap parting tools and HSS blades make decent threading tools as well:

 

[carlsbad]

Gene,
What grinding setup would you recommend for a beginner? --Jerry

 

[Stan Taylor]

Gene,
What grinding setup would you recommend for a beginner? --Jerry

This a 5/16 Hss that I ground for a lathe at work

 

[Dusty Stevens]

Hard to face off that t-nut in a lathe without a toolpost.

Id advise you stop all progress until you get these issues fixed or like my man shortgrass said youll be wearing that toolpost. If you tighten that top nut with a hard pull like leaning into it then look underneath and if you cant see light inbetween the t-nut and your toolpost AND under the t-nut then do not machine anything else. That t-nut should be able to slide back and forth in the slot easily and you should be able to rattle it up and down. If you cant- stop and fix your machine. The way that tool is jumping around youre going to get hurt. Please listen to me on this. Near misses are just a precursor to a real accident. These guys on here have been doing this a long time so sitting on the sidelines it does seem easy to just get a machine and get to building guns. You should really find a mentor- youtube videos skip over the simple stuff like tool geometry, feeds, tool position and workholding properly.