Day 1 Practice - lessons learned. 12/30 update

[Bamban]

1600 was turning down shank, not threading. I’m a turtle slow threader. I have tried from 90-200 with the hss. Not sure if finish changes or not. I’ll try it out. My carbide threading tool came with the wrong insert, so I’m waiting on new ones .... again. It had a flat tip.
Been trying up the lathe today. Ran a 1ft piece of 3/4 from the 3 jaw to a center. The diameter on the left was .021 larger than the right. After adjustment it was within .001. Very happy. One thing fixed.

12 inch long 3/4 diameter, supported on the right?

What did you adjust to correct a 0.021 taper down to a 0.001?

 

[boltman223]

I know your mentor uses carbide. Carbide is not going to make things any easier on you. Get the Arthur R. Warner threading tool and be done with it and just use the carbide for turning. Then you can spend all the time you would grinding, getting time on the machine, which is what you really need.


Later on you can perfect your tool grinding. And at that time you'll have a better basis to judge yourself on.

Keep increasing your speeds to see what happens. Trial and error is about the only way to learn in your situation. Do it safely!

I gave you a link to the recomended surface speeds and the calculator. Use it for at least a starting point. Then adjust for what you're working with. It's all about feeds and speeds. Generally speaking the faster you turn the better the surface finish. Depth of cut and feed rate can make difference too. Some tools require higher feed rate and bigger Depth of cut to get what you're after.

I'm sick of seeing your chowdered up threads. Again, Forget the carbide. Use some HSS, and speed things up, like I told you over a week ago. There is also a whole thread about what speeds people are using.

 

[mram10]

Bam, left side in 3 jaw, right side supported by tailstock center. I adjusted the tailstock via the Set screws on the base.
Bolt, I already have the hss and an Iscar threading tool. I like the hss so far but want to try the carbide when I get the correct tip.

 

[boltman223]

Bolt, I already have the hss and an Iscar threading tool. I like the hss so far but want to try the carbide when I get the correct tip.

Alright, it's worth trying. Increase your speeds though, 200 looks like it is too slow.

 

[338 Mollett]

I run an Eisen also, nice lathe for our purpose.Some thing I would like to point out if it hasn't already been addressed is to test rigidity with the same set up as if you are doing barrels that is using a copper wire in your chuck and using your spider setup.The last pic of threads looked good and I would not hesitate screwing them on any action I have .Good luck and enjoy the journey !

 

[mram10]

Thanks 338. I def plan on the copper wire with rear spider.
Need a break! I did a practice today trying for perfection. The shank turned out perfect with carbide at 1100rpm. Recoil lug barely went on and with a touch of sanding, it was solid. Shoulder was great. Trimmed face to make shank .998 which gave .010 clearance. Put the relief .010 in from the recoil lug. Again, perfect. Trimmed the threading part of the shank to 1.060. Placed a slight 45deg chamfer and the world was good..... until....
I went over and ground my hss threading tool so it was sharp. Went over to the lathe and lined up the work with the fishtail. Threading with the compound this time to see if it would look better. The threads were getting sharp so I tried the action. It started to go on. Did a couple light .001 passes and a spring pass. Action still only started. Figured something was wrong, I took off the tool and measured. It was less than 60 deg and made a mess of my threads. After a huge let down, I came inside to take a break. I’ll definitely be using the carbide threading insert to take one more variable away....

 

[338 Mollett]

On your shoulder plunge your cutter in about another 2 thou to make sure you cut past the radius formed and get a good fit between the lug and the shoulder.

 

[mram10]

On your shoulder plunge your cutter in about another 2 thou to make sure you cut past the radius formed and get a good fit between the lug and the shoulder.

Will do. Thx

 

[338 Mollett]

Something else to think about,It's a good thing to have as much shelf as you can for your lug to rest on but when you dial the breech in and you see how much runout the muzzle has on a real crooked barrel it will need to be timed at 12 o'clock .The material removed will be off that shoulder.Cut the relief groove a little farther back so when you have to set back the shoulder the shelf won't be in the way also saving time so you don't set back the relief groove also.It will be a crap shoot for now but in time you will be able to look at the threads of the action to see where they start to know how set up your feeds and slides catching the barrel just right to eliminate excessive work.Screwing on the action will tell you how much to set back the shoulder,on a 16 tpi and the high end is at 6 o'clock you have about 31 thou. to remove do so half at a time these machines LIE !Grind a small sharp hss tool for cutting out the radius at the shoulder,this can also be used to cut your crowns.

 

[mram10]

338, sounds good. Thanks.

 

[JSH]

mram, I have no input and won't clog up the thread other than to give you a big THANKS.
Also a thanks to all who have given input to all of the possible causes of issues.
I went down and tinkered with my old Sheldon. I had some chatter issues. Forget who the winner was that solved my problem but it is fixed now after seeing several things I needed to look at.
I am in luck and have a willing mentor to help me out. I have hit several local auctions and picked up a fair jag of equipment and large assortment of tooling.
Time to get mine to work!
Thanks to all again and I will be following this.
Jeff

 

[mram10]

Jsh, great to hear. Just happy my mistakes are helping These guys have been a huge help. Been busy with work, but will start back up Thursday with my new tools

 

[ab_bentley]

A trick leaned is when you need a relief on the backside of the threads, use an old threading insert to create the void, not a parting tool. The depth can be set to match the thread depth and the end result is a very clean, almost invisible relief.

Adam

 

[hogpatrol]

I may have missed it but I haven't seen anything about recommended surface speeds or feed rates and little to nothing about toolbit rake. Suggest that any aspiring machine tool operator learn these two basics before ever putting a tool to a workpiece. It would save a lot of time and frustration. The general rule for carbide tooling usage is high surface speeds and the opposite for high speed steel toolbits. In 54 years of cutting metal and working with hundreds of fellow machinists and toolmakers, running carbide slow was and still is a non starter. If you want to run slow speeds, run HSS toolbits like MoMax or Armstrong. For good finishes, run light cuts at high surface speeds with positive rake carbide bits and a moderate feed rate, .005 to .010.

 

[hoz53]

A trick leaned is when you need a relief on the backside of the threads, use an old threading insert to create the void, not a parting tool. The depth can be set to match the thread depth and the end result is a very clean, almost invisible relief.

AdamView attachment 1031054

thats a good idea thanks

 

[mram10]

Ab, I’ll try it. Thx
Hog, it is buried in the posts. Carbide 1100 or 1600. Hss for threading at 90 - 200ish