Need help and suggestions turning problematic O1 Tool Steel

I've had numerous issues turning parts with 01 oil hardened drill rod, on my CNC machines.

I use 36" lengths- import, 9/16" and 11/16" in diameter.

The problem has been the hardness varying from stock piece to piece in the 9/16".

If it's as normal it machines beautifully and accurately from part to part.

But some of it is so hard it tears up my inserts, produces a lousy finish and jumps around in size from part to part. That is the extreme and thankfully, haven't gotten any that bad lately.

What I'm finding now is 1/2 of my stock coming in is good, but then the other half produces and acceptable finish, but it will not hold tolerance from part to part, and shortens insert life.

This has only been with the 9/16" stock. The 11/16" is fine.

I'm at my wit's end trying to come up with a solution. I've tried slowing down my feed and depth of cut.

It's going to effect my business with the lack of availability and then 1/2 of it having this issue when it gets here. I don't know what to do.

Any suggestions on trying to get this hard 01 to work would be much appreciated.

Hi TSP Californian:
I would expect O-1 to be more variable in characteristics than say A-2 simply because it's oil hardened so it will be more variable just from the variability of the quench.
Skinnier bars will be worse because they can cool quicker going from furnace to oil so some will be softer especially if they're processed in bundles.
The center bars will retain the heat better, and will come out harder.

I suspect a more consistent heat treat would solve your problems...I don't know if a different heat treater is the answer, or a more expensive batch processing of smaller quantities at a time in the quench will remedy your problem.

Can you hardness test each bar and have the too-hard ones drawn back a second time?
Can you specify a closer hardness tolerance or specify a second draw routinely?
Can you subject every bar to another draw?
Remember, more is not going to be harmful in a draw like it would be in a quench, so specifying more draws costs only money.

As far as finding a golden strategy to turn the too-hard bars and get them to work out; I think you will be disappointed if you try.

So find a bar that works, investigate what you've got and try to get the heat treater to duplicate that for every bar, even if radical things have to be done in the heat treat to get those properties.
The additional cost will repay itself in the consistency of the turning.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

??? I would expect off-the-shelf O1 bar stock to be annealed, not quenched. If that's what you're buying, complain to your vendor. Until they can fix the supply problem, find a local heat-treater and do as Marcus suggests: get the bars annealed.

Well was hoping for a magic machine adjustment fix.

Yes, I have complained even sent machined samples to their broker/supplier and they so far have replaced it, but it's all import and even what they replace bad stock with, is what is yet another crap shoot.

Now, add to the fact there are shortages I can't even get replacements.

No local heat treater in my area.

Why not run the 9/16 parts out of 11/16?

TSPCalifornian said:

Well was hoping for a magic machine adjustment fix.

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A hardness tester is not very expensive. Drawing any hard stuff back is not so expensive either, you could probably do it in one of those ovens for keeping welding rod dry in.

May have to... thanks.

EmanuelGoldstein said:

A hardness tester is not very expensive. Drawing any hard stuff back is not so expensive either, you could probably do it in one of those ovens for keeping welding rod dry in.

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I need to check into this... thanks

It sounds like you need a better supplier. The one you have now is complete shit.

The suppliers I have talked to all get their steel from the same place, same countries so no luck with that. This is the world we live in today... BUT!!!!!!

I upped my IPR and to my pleasant surprise this harder crap is holding tolerances so far. The finish is not quite as good but acceptable. So far so good. Don't know about tool wear in the long run.

What is your definition of "hardened drill rod" ? why are you using O1 ? how hard do you need your finished part to be?

Hi,
What is the cutting speed you are running at?
What type of insert and which carbide grade?
When you say "tears up my inserts", tell us: Large wear / microbreakages on the cutting edge / complete breakage of the insert?

Eric

TSPCalifornian said:

The suppliers I have talked to all get their steel from the same place, same countries so no luck with that. This is the world we live in today... BUT!!!!!!

I upped my IPR and to my pleasant surprise this harder crap is holding tolerances so far. The finish is not quite as good but acceptable. So far so good. Don't know about tool wear in the long run.

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Ok then we should define your definition of "hard" because O-1 is not hard to machine.
Sure if all you're used to is Delrin and 12L14 then yeah it's hard.

Mtndew said:

Ok then we should define your definition of "hard" because O-1 is not hard to machine.
Sure if all you're used to is Delrin and 12L14 then yeah it's hard.

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I agree with this. I've never seen anywhere that sells O1 "drill rod" in a Pre-hard condition, although it may exist i guess.

It normally comes in annealed condition as others here have stated.

It is however, quite gummy IMO in the annealed condition.

How can I explain this...

If I order O1 drill rod and it arrives in a normal state it machines beautifully for me.

The problem here is they are sending O1 that is so hard it chips and tears- it doesn't curl. It produces a horrible finish. It machines inconstantly in tolerance. Even with an ISCAR cut off carbide parting insert, it will not cut flat and cuts a rounded end.

I've been doing this the same way for over 10 years. This is crap steel. Call it what you will, but all I can figure is it's hard. It creates numerous problems for me.