01 steel sharpening question

[Tom Gold]

Recently made my first knife which I posted on the forum here http://www.bushcraftuk.com/forum/showthread.php?t=133057 a couple of weeks back.

It turned out just how I wanted it to look but I cannot get it sharp. Its 4mm 01 steel which I heat treated to cherry red non magnetic, quenched in cooking oil and baked for 2 hrs at 215. I gave it a sabre grind.

I have battoned it through some seriously tough knotted wood many times without even the slightest marks on the blade or dulling the rather poor edge I have been able to put on it and it can throw a great shower of sparks off the spine on my ferro rod but it just wont sharpen up like my Mora Black.

I have used oil stones, sandpaper and have stropped it til my arms ache on an old leather belt but still cant get it to cleanly take the edge of a sheet of paper.

My boys want me to make knives with them this holiday but until I figure this out I dont really want to start another knife.

Is this steel very different from that used by Mora? Is it too hard for oil stones? Is it possessed of the devil? Any suggestions as to what I'm doing wrong or or something I might have missed when I was making it would be very welcome.

 

[mick91]

I've had similar issues as I'm pretty new to smithing and knifemaking too. Try out a diamond based sharpening stone like a falkniven set. Shouldn't be resisting oilstones though. Look at some tutorials on honing razors and knives too you may find it's not as easy as it looks and a good technique really helps.
I've been advised by a couple of pretty well established blacksmiths to quench in brine too. I don't see a major difference but I'm sure there will be one. I've been using 410 surgical stainless though

 

[mark.177]

o1 takes a razor sharp edge and holds it very well if heat treated properly, theres a couple reasons it may be hard to put a razor edge on it...

poor sharpening technique or wrong choice of equipment?
it may have been over heated during heat treat which would cause grain growth
de carbonation would leave the edge soft
under tempering would leave the edge very hard
215c is very low! i temper o1 at 260c for an hrc of 60

 

[Tom Gold]

Thanks chaps, thinking I might just have made one hell of a letter opener. Yep whole heat treat was pretty much groping in the dark.

Btw Mark, what is grain growth?

 

[Juggernaut]

worksharp, got one a while ago from Hennie Haynes, theyre very easy to use and provide a paper cutting edge in a few minutes.

will set you back anything up to £100 depending where you get one from but a worthwhile investment, I used mine on my bushcraft knives as well as my M&S kitchen knives lol

 

[mark.177]

Thanks chaps, thinking I might just have made one hell of a letter opener. Yep whole heat treat was pretty much groping in the dark.

Btw Mark, what is grain growth?

as simple as i can, its the grain structure of the steel, in a good blade it will be very fine but... over heat the steel and it becomes course and week.

 

[Robson Valley]

Are you freehand sharpening? If so, are you holding your forearms tight to your sides?
If your elbows move, you lift the blade and round off the bevel at the end of each pull pass.

 

[Draven]

Both too hard and too soft steel will get sharp. Soft steel will generally have problems with a wire edge (it will easily form a wire edge that will not easily detach) and it will dull quickly, whereas hard steel will be very difficult to sharpen. I think your blade might be too hard - I agree that 215 sounds very low temp for tempering o1. What color was the blade when you took it out?

Grain structure essentially refers to how fine or coarse the crystalline structure of the steel is. Uniformly fine grain dramatically improves the blade's strength and sharpenability. Best bet is normalize it - heat it to critical, let it cool slowly. Do that three times and then do your heat and quench as normal, then temper. Problems with grain size are often found with forging (where different parts of the steel are being heated more than others and the whole thing is being heated repeatedly and hammered on) and power-grinding (where you might inadvertently heat up, say, the tip of the blade too much).

Before I got to any of that, though, I'd run a file on the bevel and see how that reacts. Do the same on a piece of mild steel and compare - if the file bites the blade like the mild steel, it's too soft. If it doesn't bite it at all, it's too hard. If it seems good on that test, I'd keep sharpening. What kind of oil stone do you use? Those grey hardware store carborundum stones are pretty poor sharpeners for knives, though they can work with patience - they work better on softer blades. Using sandpaper or diamond, I'd go to 220 grit or so and do that until it's sharp. I wouldn't touch finer grits until it's sharp enough to cut a tomato.

Also worth doing is holding it up to a light surface and trying to see what angle the cutting edge is. secondary bevels that are too obtuse can feel like butterknives even if they're sharpened right.

 

[Shinken]

I would say it is probably something to do with edge geometry, either thicker at the edge than the mora or different sharpening angle. If you put a woodcarving angle on it about 30 degrees then that might be the difference you are experiencing as the mora has a more acute angle. That being said they should both get sharp.

 

[mrcharly]

What draven said. You can sharpen copper to paper-slicing sharpness, but it won't last long.

I think you need a magnifying glass or something to see what is happening with your edge.

 

[Tom Gold]

Many thanks for the advice guys, got plenty to try now. I like the idea of 'normalising' going to try that next time Draven, thankyou.

Was told 01 is very forgiving so am hoping its a sharpening error - I'll keep the elbows in next time Robson.