440c or O1 - Another Metal Question...

Chris Crawford

Chris Crawford

Joined
Apr 14, 2001
Messages
380
The post about ATS34 or 440c got me thinking...

I've never used stainless, and so far my steel of choice has been O1. My question is for anyone who has worked with both O1 and 440c. Can you compare the the two in their ability to be worked, toughness, and edge holding ability?

I'm planning on making one of my scale release autos with pearl scales, and I thought 440c steel may be a good choice because it would not turn dark over time like the O1 will.

Any ideas or opinions?

Thanks -chris
 
Chris , I 've been working in O1 for about six months and just started working with 440C. I like O1 and wanted a easonably prices stainless known for its reliability and performance - so I went to 440C. I did a couple straight blades in what were ambitious grinds (for me). No problems and the steel was excellent to work with. I did the 45's with a 36 grit, did most of the bevels with a 50 and then went to 220. Nice and smooth.

From there on, you will probably get more informative posts from others, as the blades are now at Paul Bos for heat treat. I'm curious as to the comparison in ease of finishing. I've been told that edge retention should be excellent.

Bob


http://www.southrivermodelworks.com/page15b.html
http://www.southrivermodelworks.com/
 
Chris
if your interested I just posted in the thread
ATS-34 or 440c ???
but anyway I use O1 because of the ease of the heat treat
and very easy to sharpen and deep freezing is not
necessary on O1,
you know this anyway by past use of it.
Go both ways and offer the difference to the customer.
but I'd go with the better SS if your going to bother with it
just because it's SS. just 2 more cents..
:)
 
Properly heat treated 440C(Paul Bos or=), will hold an edge as well or better than O1. It is fairly easy to resharpen. :)
 
Is it possible to forge with 440c? Does heating it in atmosphere degrade it like welding it without covering gas?
 
It can be forged, at lower than normal temperatures. Problem is, it's still 440C when you finish. You don't benefit by forging, and there is a considerable chance it will be the worse for the effort.
Most of the high alloy stainless steels were made to not need forging. Thats whats so neat about them, to me at least.:D
 
Chris about 2/3 of my production so far has been 440C. Of those I only know of one that's seen "serious" use and it's skinned one or two deer each season for over 10 years and not required sharpening. This is as reported by the owner, I haven't seen the knife. It was heat treated by TKS. I've had two recent 440C knives quenched in nitrogen but no reports back so far.

I recently switched to O1 to take advantage of the shorter turnaround time for HT. I often use the dry ice/acetone quench and have heard - haven't tested myself - that it holds an edge better than any high end production knife in either owner's experience. One set of these is carving wood, the other cutting meat.

As to working the steel, I think they're very similar - O1 might be easier but if so it's a marginal difference. For a knife like you describe I'd go with 440C and a cryo quench. A blade like that will suit any owner just fine.

I'd love to see one of your scale release knives. Also, how did your sunfish project turn out? Do you have a pattern you'd share? I've been studying your slipjoint tutorial, have purchased some steel for one and think a sunfish would be my preferred first knife, since I want one and can't afford it. Just a thought. :)

Dave
 
Don, yes to both but I do understand that the deepfreeze will undo any benefits of the edge quench.

Dave
 
Graymaker's question is a good one. I can't believe that
freeze treating will have any detrimental effect on the O1.
If you do a temper after the quench, to stress relieve, and then
freeze, the steel should be improved if anything. The soft back
should remain soft and the edge hard. Maybe a harder edge.
 
I've been away from the forums for a few days, but thanks to everyone for the info about working with 440c and O1.

Dave, I've never gotten around to making that sunfish yet. Somehow I always find other projects to do. So many knives to make, so little time. However, sense the time that I was asking about the sunfish pattern, I've picked up two Case XX sunfishes. I don't have the heart to take them apart for the pattern though.

I'm pretty excited about these little scale release autos. After being inspired by Peters video, I decided to try to shoot a video of making the auto. I tried this once before, but trying to film while trying to make the knife really slowed me down.

-chris
 
As to the cryo undoing the differential hardening - I read it somewhere else, but the idea is it's the same effect as quenching the entire blade out of the fire - you're just going from room temp to minus 300 or so rather than 1500 to 140. But I'm no metalurgist, just what I read and it sounds reasonable to me. I'd like to believe my differential hardening would withstand the deepfreeze!

Chris I know what you mean about taking one of those beauties apart - I bought one too. :D I may just have to promise myself to put it back together with something better than the jigged bone...

Looking forward to your video.

Dave
 
Dave, I would say that cryo would not have any effect on your temperline. Can't believe what you read anyway, it was probably printed by the news media.;) :D
 
Yeah Mike - internet spawn. :rolleyes:

I'm glad to hear the arguments to the side I prefer! I guess a good test would be to (try to) break one done each way and see if there's a difference.

Dave
 
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