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Need help - Turning unknown Material

jephw

Aluminum
Joined
Jul 23, 2020
Good day all. Rookie machinist here.
Here's my scenario: got a 4 inch round stock of material I need to make parts from, and I do not know the properties, but does seem about medium hard. I have ISCAR IC907 CNMG inserts to do this job. Work is to be done on a Mori Seiki Nl3000.
I have tried a little bit but keep wrecking inserts.
Do I start with low/high sfm? What about ipr? Doc?
When you guys have material with unknown properties, what are ways to approach such a situation?
Thanks everyone in advance.
 
Is the outside shiny? Is it magnetic?

What speeds and feeds have you tried?

BTW that's a helluva lathe to be dinking around with mystery metal. How is it the shop owner turned you loose under these circumstances? How the heck could no one have told you what you are working with?

Regards.

Mike
 
Not sure what the circumstances are here, does the boss know what type of alloy it is? If not I would take it to someone who can shoot it for a couple bucks, there by giving you a starting point. Or just watch listen and see what info you can glean and proceed from there. Sorry I do not have a more viable suggestion.
Best of luck to you,
D
 
It is magnetic. It's a piece picked up from the scrap yard so the outside is all rusty and also explains why I don't know what I'm working with. Steep learning curve for sure.
I've tried 300sfm, .005 ipr with .04 doc. Had the insert burned up in the first 8 inches. Figured I'd ask here before I try more.
 
"The high cost of being cheap". After cooking a couple of those inserts and the waste of time how much did the owner save? I wish I could help with the speed and feed but rusty magnetic doesn't narrow it down very much.
 
Suppose a hardness tester is out of the question eh? Take a sharp file and see if you can file it easily or does the file skip? Can you take a small HSS drill and try drilling it somewhere? more than one way to skin a cat. Wild guess is your .005" feed might be just a little light .
 
Looking forward to all the advice here.
A touch of info on wreaking inserts might be helpful. Worn hard or broken or do not know since there is no tip left.
Bad cut before it gave up?
To be truthful I after only 47 years in carbide and Dad many more I do not have enough chips in my shoes to answer such a question.
For sure others here that can nail it so I look to them for the knowledge I do not have and wish I did.
With that I say goodbye to the board because despite my try in many different things here I just do not know anymore and the kids are so top notch.
Bob
 
Could be something that was case-hardened. Try half the speed and 2-3x the feed.

What shape and color are the chips?

Regards.

Mike
I will try that and see how it goes.
Wasn't even really producing chips with the speeds I was trying, seemed to bird nest if anything.
 
"The high cost of being cheap". After cooking a couple of those inserts and the waste of time how much did the owner save? I wish I could help with the speed and feed but rusty magnetic doesn't narrow it down very much.

I agree. Likely be the last time this will happen. Although there are tools available, like a portable hardness tester, to make this somewhat sensible.
 
Looking forward to all the advice here.
A touch of info on wreaking inserts might be helpful. Worn hard or broken or do not know since there is no tip left.
Bad cut before it gave up?
To be truthful I after only 47 years in carbide and Dad many more I do not have enough chips in my shoes to answer such a question.
For sure others here that can nail it so I look to them for the knowledge I do not have and wish i did.
With that I say goodbye because despite my try in different things I just do not know anymore.
Bob

From what I was able to see it seemed like the edge just wore right down, and then broke off after a short time running with the dull edge.
 
A file will bite in, but slightly. Based on that, I assumed the medium hardness. :D Another note, I could not cut it with a bandsaw, had to use a chop saw instead to get a chunk to work with.
 
Having an alloy of unknown compositions and hearing folks talk about files bighting or not bighting brings to mind getting a set of hardness files. For a good set ~85 or so bucks sounds like a good idea. Our shop is to thrifty to buy, but I like my set they can give you a pretty inclining of hardness.

Just my .02
 
Forrest wrote a good piece on "mystery Metal".

What is this part expected to doo when completed ?
 
A file will bite in, but slightly. Based on that, I assumed the medium hardness. :D Another note, I could not cut it with a bandsaw, had to use a chop saw instead to get a chunk to work with.

Might have tried opening with the fact a bandsaw wouldn't cut it. Send it back to the scrap yard where it belongs and select a known material whos properties are what is required by the part.
 
I ain't going to try and guess what material it is. But I could get it machined.

I would start at 150SFM..01" Feed per rev. .1" DOC. .0312" corner radius on the insert. If that eats up your insert only slow the spindle speed, don't change anything else. Until you get the speed right.

OR put a chunk on an Engine Lathe and whittle at it for a minute.

I'm right there with you Bob.

R
 
OR put a chunk on an Engine Lathe and whittle at it for a minute.
R

I would say this is the best advice so you can get a feel for what is happening before you smoke tooling. I used to do that quite often when I had a material I had not worked with before back in the day when information wasn't always readily available.

I can't believe your boss has you using a 4" chunk of rusty mystery metal in a nice large CNC lathe, that is stupid to say the least. Mystery metal should only be used on a nice machine as a last resort in an emergency only. Like it's Saturday morning and a coolant pump goes down, and you need to make an adapter plate to mount a spare you took from a machine you scrapped out. The only mystery metal I have used in a pinch has been pulled from my own scrap cans so I can make an educated guess on what it is.
 
I'd try annealing it a bit, just on the bench. Even if you cannot get it up to full red hot for an hour, if you can spoil the temper of it by heating it up past the tempering colors range, or as hot as you can and letting it air cool, then good chance that it is a plain or low alloy steel. Cutting the piece off with a chop saw likely made a super hard skin on it, too, which can ruin your tool immediately. For sure, do the test cutting on a manual lathe so you can feel via the hand cranks how much resistance it is putting up compared to some identified chunk.
 








 
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