Weird O1 etching... help, please!

Chiro75

Chiro75

Joined
Feb 4, 1999
Messages
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I used O-1 for the first time last night and I was amazed. Easy to drill, easy to cut with my hacksaw, grinds nicely, and the precision ground finish was a nice way to start the knife off. Compared to 1084 it was a dream to work with, and it seemed a lot less touchy than 1095. Everything was great until the etching. I couldn't get clay to stick to it last night, so I went with just a normal differential oil quench, no clay. File skated right off the edge all the way along. Immediately went into 400° oven for 2 hours. After cooling, I did some more grinding and then hand rubbed to 400 grit, etched in ferric chloride and took the pics attached below. So, now I want to find out if I goofed something up, or if my experience was normal and I just need to refine my process...

The first thing I noticed was the difference in etching time. With 1084 or 1095, which is all I've used, I stick the knife in my FC solution and within 10 seconds I can see my temper line. For a dark etch on either steel I can go 30-60 seconds and my etch is fine. On the O1, I went forabout 10 minutes and it still had a very light etch.

I thought maybe my finish was too rough at 400 grit, so I took it to 600 and it actually etched worse.

On the pics you can make out the temper zones, but the line is non-existant, and there is some weird "graining" in the softer zone. You can see that on the pic where the tip is up best. Please check out the pics and let me know if/what I did wrong and what I can do to improve my technique on this steel. I really liked O1, but should I forget about differential HT'ing it and just do a full quench? I know it can be done nicely, so I must have screwed up something...
 

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O1 is an "air hardening" steel and will respond differently to an edge quench. The etch looks about right. If you want a more distinct line you'll have to get the clay to stick. BGoode has this pretty well figgured out and can advise when he gets back from the Blade. I'll mention this to him when I see him later today.
400 on the temper may leave your edge a little brittle. I've found that 415 to 420 gives a better working blade that's not prone to snapping off at the wrong time. I've done a lot of bending and edge test on O1 and have had blades snap in half with 400 but bend 90 + deg with no cracking at 420.
I use a lot of O1 and love the stuff.
CRex
 
Chiro, You can get the clay to stick to the surface of just about any blade if you coat the blade with borax. heat just enough to make it run and coat the surface. Let the blade cool then apply the clay.I leave the borax coat a little ruff. It helps the clay to stick.

Carl, I didn't realize you could air harden o-1. Inlighten me on this point. Thanks Fred
 
Fred, I think the problem was that I forgot to clean the blade off of tapping/drilling fluid before coating it. Two different materials popped right off when they hit the forge to heat, so I took the lazy route! :D I know Brian gets pretty decent temper lines, although still not anything like 10xx that I'm used to in terms of the clarity of the line itself. That's frustrating. My problem is that O1 seems to be the easiest stuff to work out of what I use, 1095 is cheap and works well, but the hamon is so-so, and 1084 gets the best hamon, but the material itself drives me crazy (for some reason I have a lot of trouble drilling it, and the HRA stuff I get has thick, nasty, junky scale all over it). What a mess.

I like the general gray-ish appearance of the O1, so I might just forget about edge quenching, dump the whole works right into the oil and then etch it for a nice color. I'll give the clay a shot over the weekend, too, and see if I can get that to woork out a little better.
 
The 'O' on O-1 stands for oil hardening .Sometimes these steels , in thin sections, may harden in air depending on composition..The best chance for a hamon is to differentially quench and putting clay on the spine and differentially quenching might work even better.....O-1 makes an excellent knife and works fine with forging or stock removal.
 
I'll try one with clay this weekend, then. Just got my bandsaw blade so that should speed things up a bit! :D
 
Chiro,
My first reaction when I "read" the etch is that you may not have gotten the steel hard enough. You should see a bold difference in the grain and color fron the softer top to the lower area after you etch the blade. When I use 3 to 1 ferric solution I see a bold difference within seconds and a black hardened area and a gray softer spine in very little time.
Try the heat treat again and get the steel just about 5 to 7 seconds hotter from where you were before.
Here are some pictures I have that may help.
I use a torch to sort of paint in my hardening area. Very easy to burn the steel! If you start to see lizard skin in the etch the steel was burnt a little.
Just learn as you go :D
This first picture is for CREX :p
Right.jpg

variousfeb2.jpg

Bobs.jpg

cocobolo_standard.jpg
 
Brian, I think you're right. I sharpened the knife up last night and it sucked. But it's 3/16" and I'm used to 1/8", so I thought maybe that's just the way it is. But, this morning I cut out and drilled a few blanks and I picked up the same file I used a couple days ago to test the edge on the O1 knife and the file is dull as hell! :rolleyes: So, I think it didn't get fully hardened, too. Honestly, this NEVER happens to me! ;) Anyway, I normalized it a few times and I'm going to take a second run at it in a couple hours. How was Blade?
 
Blade was BIG. Didnt get to see all I wanted or buy the supplies I didnt want to order :mad: Great though!
 
Brian,
Glad you made it home safely. Good to see and talk with you as always. Try GoJo. Some gal in Alpharetta, Ga got your donated knife this morning. Man the place was hoppin this morning. John and I finally gave it and went home around 2:30. Dogs were dead. Sandy said he's sorry he missed seeing you. Happy Anniversery Friend!

Yeah, I know the "O" in O1 stands for Oil hardening. You don't believe it will air harden, bring a blade up to critical and soak an extra second or two. Bring it out and wave it around in cool air or hold it in front of a fan. I think you'll find out the "BOOK" is a guide line not a steadfast fact. We're not talking 1" thick stock here but very thin, fast cooling blade profiles. No, it won't get skate-a-file hard with room air but it will get appreciably harder than annealed. It will actually be harder than blades in many store bought pocket knives. O1, 5160, and 52100 to name a few, all air harden to some extent.
 
Nicethat a girl won the knife! Ladys always smile when they see the Small SideKick.
Hope she emails me so I get her reaction.

Good to be around friends CREX. You guys are like family! I hate I missed Sandy but soon we'll be hearing the ping of anvils at TrackRock!
We had a good night out at a comedy club and I have 2 rough shaped handles ready to get smoothed up after church. What a day....I cant ask for more! :)
 
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