O1 steel???

[sticshooter]

OK I have used O1 just a couple of times. And I must be doing something wrong. Drilling this stuff is harder then sawmill steel. I heat it up and hammer it Then when I get what i want I heat it up and let it cool slow. But even with cobalt bits I can drill it. It almost seems like its already hardened? So anyone shine some light on this? I got some O1 and 5160 flat stock and wanna use it but geewhizz drilling it is no fun and tuckers me and my drill out!LOL<><

[kbaknife]

It seems like it has hardened because it HAS hardened.
5160 and O1 are deep hardening steels and have lots of alloy.
You have just now experienced one of those reasons why some steels are NOT conducive to knife making for the maker without things like controlled ovens.
When you heat up O1 - you didn't really say it, but I'll guarentee you that you went up past non-magnetic - to non-magnetic and then let it cool, it is such a deep hardening steel that it begins to make martensite almost like it was stainless steel, which is air-quenchable.
To work O1 after forging, you would need to soak the steel IN AN OVEN at a sub-critical temp less that 1414, soak it for about an hour, and then slow cool.
As soon as you create austenite, which you will do when you get not very far above non-magnetic, you set up the steel to begin making martensite.
That's the reason for the sub-critical soak, so that you can spherodize the carbides without creating martensite.
If you are just drilling tangs, what you can do is turn the lights off in a dark room.
With an O/A toch and a #3 welding tip, just bring up the area you want to drill until it turns a dark red in a dark room.
When steel turns red in a dark room, it's at about 1000 degrees.
Remove the heat as soon as it turns red.
Let it cool.
Do this three or four times and then try drilling it again.
Or, forget O1.
I made you a "guarentee" above, and I'll make you another one right now:
There are all kinds of "makers" out there who will say, "Oh, I've used O1 penty of times and I don't have an oven and they come out just fine.".
Yep. And they're using coal forges and propane torches and quenching in goofy muixtures of transmission fluid and motor oil and canola oil and all sorts of weird things.
Truth is, they've NEVER dealt with properly heat treated O1 and have never seen what it can do or how it acts.
They were MAYBE successful in getting only a partial completion of martensite on the skin or the very edge.
What you've done is hardened the outer skin in the air. Your drill bits are dulled before they can even get through it.
As a matter of fact, even if you are drilling annealed O1, you can heat up the steel AS YOU DRILL and create martensite and all of a sudden your drill bit just DIES right in front of your eyes.
5160 will air harden as well.
As soon as I have three or four blades forged out and have done the post-forging thermal cycles and normalizing, (which is all done ABOVE non-magnetic) it's a 100% guardentee that I have air hardened at least SOME of the steel.
I put that batch of blades in my oven and soak them at 1375 for two hours and program the oven to cool them slowly down to about 1000 degrees.
Then I can drill them with any ol' drill bit in the shop.
There is absolutely no need for high dollar designer drill bits if you just simply spherodize your steel.
Or, work with steel that won't air harden.

[sticshooter]

Thanks Karl. I will try that. And also try just drilling the holes in the tang before I hammer and blade shape. The one I have now I am going to heat up like you said just the handle and then let it cool and try drilling. The 5160 I used I drilled and cutout the shape and did stock removal. It drill fine. <><

[kbaknife]

Yes, that 5160 WILL drill just fine because it came from the mill in a spherodized condition. But, once you do some forging and bring that steel up to an austenitic condition, you begin to get air hardening.
So, you then need to re-spherodize.
Since you are not doing a complete spherodizing action with that torch, you MUST make sure that you do it three or four or five times and that you NEVER once go above 1414.
You just want it a dull dark red in a dark room.
Once you see "color" start, back off and let it COMPLETELY cool down.
Do this numerous times and you might be OK.

[Kevin Evans]

Karl ,Do you agree with this?after it goes through the thermo cycle immediately go to the vermiculite,
(not many have the oven to let cool slow),therefore if you put in vermiculite or sand or ashes you will get a better effect of softening the steel.

After you explaining this to me over and over I'm really starting to understand what goes on

[kbaknife]

It depends on WHAT steel Kevin.
Not O1.
Read above - you don't want to slow cool a deep hardening steel like O1 AFTER you have taken it ABOVE non-magnetic, which is exactly what you are doing when you do your thermal cycling and normalizing!
I'll bet I have seen 200 posts on various forums about guys wanting to know "What kind of drill bit do I need to drill O1?"
You can drill O1 with cheap "Bargain bin" drill bits if you simply spherodize the steel.
Doing those post-forging thermal cycles does a lot toward stress relief and grain size reduction, but plays heck with hardness on deep hardening steels.
When you do those same cycles with shallow hardening steels, they have so few alloys that they revert to pearlite in just a second or two and don't make martensite, so feel free to take your W1/2, 1084 and 1095 and heat them up and bury them in whatever.
(Actually, lime is a much better insulator than vermiculite, and you probably buy them both in the same store!)
But when you slow cool 5160 and O1 from ABOVE the austenitic temp, which you will be doing when you thermal cycle, then you are going to get some martensite and drive yourself crazy trying to drill holes.
If all I had was a forge as a heat source for forging and thermal cycling, I would stick with 1080/1084, maybe 1095.
Once again, I stress that point about all kinds of guys saying "Ol' Karl's nuts. I've been using O1 for years and it works just fine with my simple 1 brick forge."
Truth is, the reason they've been using it is that it's so easy to find.
It gets a LITTLE hard just by looking at it and they think they've made some kind of cool knife, when in actual fact, they've only had partial success and even with only that success, it works better than any knife they've ever owned.
Want to know how hard O1 gets? It's one of the most used steels to make drill bits!!! End mills!
And all they did was follow the methods I've described above.
Can you say your blades made of O1 get as hard as drill bits??
O1 is O1.
If you get full martensite transformation by following the proper sequences, your blades will be as hard as DRILL BITS on the edge when you quench them at the right temps in the correct oil.
Then, you manipulate the RC hardness with your tempering temps.
That's what tempering is for.
Now, if you are really good, and have THE FORCE on your side, you can take your deep hardening steels and by using your forge, just baaaaaaaarely get the steel to the point of a little redness and let cool slowly.
But make sure you do NOT get over 1414, which is the currie point for iron. This should allow for some softening of the steel, which is the result of the carbon pooling up in little clumps - or "spheres" - hence the term "spherodizing anneal" which is NOT to be confused with a FULL ANNEAL.
The anneal I am referring to is an annealing cycle which is the result of SUB-CRITICAL cooling.
To accomplish this correctly, one would need to have controlled cooling which is best accomplished in a digital oven.
Doing otherwise is a little bit of guess work.
Work with steels that match your tooling and ability to control the outcome.

[sticshooter]

Should be able to drill before you apply any heat?<><

[kbaknife]

If you bought it as mill steel, for the most part, it comes in a spherodized condition.
But be warned, that most steel companies are under the assumption that the people buying it will have at their disposal both the knowlege AND the equipment to manipulae the steel furthing into the condition they desire.
In other words, the steel may indicate that it is in the spherodized condition, but the degree to which it is even and consistant is a coin toss.
I guess you could say that that is one of the benefits of proper forging is that it helps to equalize the condition of the steel, if it wasn't equalized when you got it.
But, to work it easily, one needs to have the ability fo spherodize it after the forging has taken place.

[sticshooter]

Thanks Karl. I did some heat where I wanted to drill. And drilled like butter. I took a piece that I did not heat and it drilled also very easy.
 Thanks for your help. ya know some of us POOR  FOLKS don't got all the fancy scmanzy tools and do'hickys   . Kinda make do with whats we got.    LOL<><

[kbaknife]

The best way to make do with what you have is to work with the simpler steels.
"Simpler" doesn't mean it won't perform as well.
1084 will cut like a big dog!!
You'll just never get the most out of O1 without long controlled soak times when it comes time to austenize.

[sticshooter]

Karl i get ya. Already looking to get some 1084.<><

[ALW]

I made a couple from O1 a while back.  I am a novice at knife making but decided to use O1 anyway.  The stuff I bought was annealed but it is a bugger to drill, even with better quality bits.  I wore out several new bits.  I happened to find some old 1/8" bits in some stuff from my grandfathers.  They look like tiny masonry bits.  I assume the tips are carbide.  Anyway, I chucked one of them up to see how fast I could ruin it and it cut through the steel like butter.  Don't know what kind they are or who makes them (or even if they are made any more) but they worked great.

Aaron

[kbaknife]

Originally posted by ALW:
 .......The stuff I bought was annealed but it is a bugger to drill, even with better quality bits.  I wore out several new bits.  
Aaron

See what I mean?
Just like I was saying above - steel you get DIRECTLY from the mill is SUPPOSED to be in the annealed condition.
IF!! it truly was annealed, it should be like a piece of cake to drill.
 But, they assume that it is being purchased by someone with the capabilites of further working it into a condition of easy machining.
If that very steel you refer to was to be soaked in a contolled oven at a sub-critical temp at around 1375 so as to avoid any possibility of grain growth, and then slowly cooled, it would literally be drillable with drill bits that you can buy at Wal Mart.
Yet would still be in a condition where all of the carbides are pooled up and ready to create martensite, with no grain growth and long soak times that can be attributed to steel that has been FULLY ANNEALED by bringing up to ABOVE critical and then slow cooled.
When you do full anneals, you still need to then reduce grain size and soak for extra time to get all of the carbon back in solution.
That's the wonder of the sub-critical anneal.

[ALW]

Thanks.  That's good to know.  Great information here.

Aaron