What's new
What's new

Anyone having success using Tungaloy Inserts for turning

ranchak

Cast Iron
Joined
Dec 4, 2007
Location
Southern California
I've been using Tungaloy inserts for turning SS and 4140 and have had very little success. I was wondering if anyone else is using any Tungaloy products and having success. I use Korloy for aluminum and get great results. I've tried multiple grades, chip breakers, ground, molded and still do not get a great finish or long life. I'm talking a few parts before the inserts start to fail. The parts are usually around 1.5" diameter or less. My turret is trammed to the spindle, no excessive stickout. Current job is 1.125" 4140 run in a 20C collet sticking out 3.0". Without getting into great details this is a simple part, nothing fancy. The one thing I noticed is to get an acceptable finish I really need to run these inserts at their max SFM and IPR. I'm starting to suspect the material, but it's supposed to be domestic. I've had very little luck with their parting inserts. And yes I've talked to the rep and the factory, but that hasn't seemed to help.

Flame on!!!
 
You need to give us some more information. Speed/feed/depth of cut? Coolant or dry? Hardness of bar?

Plainly put thought, anybody's P20-P10 grade, CVD coated inserts in a medium chip-breaker should work pretty well in 4140. I always noticed a threshold of about 800sfm for roughing any kind of alloy steel. Anything faster, and tool life really started to suffer...

Stainless can be all over the place. 304, 316 will be way different than 416/420, or 17-4ph... 400-series will cut like steel. 300 series, not so much, and you'll need a different grade chip-breaker to really optimize.


Like I said, we need more specific info from you.
 
Tungaloy have been my first choice for turning for the last couple of years, at least as good as the other premium brands.

They have grades and geometries for every conceivable material and application, and all the ones I've used have been excellent.

Your post is too vague to determine the issue, but it's not Tungaloy.
 
on a mill I often run at higher than recommended sfpm.
.
when depth of cut is too low you can get issues with chip not hot enough. just saying you might need to go past recommended sfpm to get better results. and yes tool life goes down. i often get a mirror like finish but rarely get much over 60 minutes tool life.
.
yes inserts can be sensitive to stuff but when they work they work really good. its a learning curve to find what works best
 
to get an acceptable finish I really need to run these inserts at their max SFM and IPR.

How much stk per side are you leaving for a finish cut?
4140 isn't anything special, what SFPM and IPR are you at while finishing?
We typically leave .01" per side for a finish pass on X.
 
I'd also double-check that your collet is holding the bar firmly. If you're getting excess vibration from the bar rattling around you'll pound the insert edge to dust pretty quickly.
 
Roughing 450 SFM, 0.002 IPM, 0.07" DOC, 0.050" Left for finishing
Finishing 550 SFM, .0025 IPM

Coolant is 585XT, concentration at 12%

I have no idea of the hardness of the material. It's 4140. Unless I take a large depth of cut and push it hard it just smears.
 
It's been a long time but I have used them with no problems - 4140ph, A2, D2, S7. I suspect it is something in your setup/holder/speeds&feeds.
 
Roughing 450 SFM, 0.002 IPM, 0.07" DOC, 0.050" Left for finishing
Finishing 550 SFM, .0025 IPM

Coolant is 585XT, concentration at 12%

I have no idea of the hardness of the material. It's 4140. Unless I take a large depth of cut and push it hard it just smears.

IPM? Are you sure?

SFM is too low IMO, and too much stock for finishing. Also kind of light on doc for roughing, but only you know how rigid everything is...
 
Roughing 450 SFM, 0.002 IPM, 0.07" DOC, 0.050" Left for finishing
Finishing 550 SFM, .0025 IPM

Coolant is 585XT, concentration at 12%

I have no idea of the hardness of the material. It's 4140. Unless I take a large depth of cut and push it hard it just smears.

.
try 600 sfpm
700 sfpm
800 sfpm
900 sfpm
1000 sfpm
yes i know its fast but as long as just taking finish cuts you need a minimum sfpm to get shiny surface. usually you reach a sfpm where tool life and surface finish are ok or a good compromise
....minimum speed its like breaking the sound barrier. need minimum sfpm to break the shiny surface barrier. too slow or right at the edge of min sfpm you can get instability
 
I tried a .010 and .020 finishing pass, it was all smeared. Even at .050 the finish was terrible

milling I take .001 to .003" DOC on a lathe thats .002 to .006" on a lathe
feed .003 ipt or ipr for lathe
.
just saying below minimum depth amounts its unstable cause chip not hot enough. feed below minimum i see no improvement in finish
 
I tried a .010 and .020 finishing pass, it was all smeared. Even at .050 the finish was terrible

What is your nose rad? .050" is a pretty heavy finish pass. And, are you sure your roughing at only .002/rev?
Should be able to rough at, at least .100"doc, 450sfm, .010"/rev
 
.004 nose radius will never get you a good finish. Use a tool with .0156 or even .0312 for better finish.
 
What is your nose rad? .050" is a pretty heavy finish pass. And, are you sure your roughing at only .002/rev?
Should be able to rough at, at least .100"doc, 450sfm, .010"/rev

Ehh.. I wouldn't do that personally with a .004"r tool....

Is the OP roughing and finishing with same tool? I would be roughing with a .032"r tool adn finishing with a .015"r @ .004-.006ipr...
 
If you haven't solved your problem yet I can dig up the program and tooling on the last batch of 4140 I ran and post the details. That one was 7/8" sticking out 3-1/2" with a live center. That was just shipped a week ago. I also run up to 1-3/8". I have noticed with the annealed the material can be a little inconsistent, but I get good finishes and tool life. I know I feed a lot faster and use much larger nose radii without even looking it up. I get 150-200+ on a set of tools, that includes making a 3-1/2" long thread, the rougher and finisher.
 
Tungalloy inserts you have to get type for material being machined. it makes a big difference
.
for example inserts made for cast iron work poorly on plastic. inserts for unalloyed aluminum and uncoated work better for plastics cause they are sharper edge. just saying look for inserts made for SS and 4140 or a similar material
.
i believe they require higher sfpm because the heat and edge prep tends to burnish surface shiny. if sfpm too low material sticks to cutting edge then breaks free periodically giving a wavy dull finish from .0003 to .0005" TIR. when cutting just right, waviness often .0002" TIR and so shiny you can see reflection in surface like a mirror
 








 
Back
Top