Question about 420HC

SC_Dave

SC_Dave

Joined
Jul 29, 2010
Messages
187
When sharpening a Buck Stockman using my DMT Diasharp plates I got a decent edge but it was a little ragged, even coming off the EEF plate. When testing the edge on notebook paper it slices the paper with a "hairy" cut. Looked at the edge under 20x loupe the edge shows some micro chipping. Suggestions?
David
 
420HC has a strong tendency to leave tenacious burrs on the edge, which I'm sure is behind the 'hairy' cutting you mention. Chipping isn't likely at all; more likely the 'chips' you see are the deep gouges left by the diamond. 420HC, with it's relatively low carbon content and high chromium, is too ductile to chip at the hardness set by production manufacturers (Buck @ ~58 RC +/-, Case's 'Tru-Sharp' version is softer @ ~ mid-50s RC).

If re-bevelling on diamond hones, even the finer ones, they'll rip through this steel easily, which leaves the edge very toothy, if not downright ragged. I've been in the habit of at least fine-tuning those edges on wet/dry sandpaper (400 grit or higher), which is a bit less aggressive, and will do a better job of cleaning up the ragged burrs left by the diamond. More often than not, I don't even use diamond for 420HC anymore. After the sandpaper, I strop on green compound on leather (this steel really responds well to it), followed by bare leather. I personally prefer using sueded leather for this (both with compound and bare, on the inside face of my leather belt).


David
 
Fanglekai said:
Are the DMT plates new?

Are you using light pressure?
Click to expand...

Plates are broken in but I think I could use less pressure. Thanks.

Obsessed with Edges said:
420HC has a strong tendency to leave tenacious burrs on the edge, which I'm sure is behind the 'hairy' cutting you mention.

If re-bevelling on diamond hones, even the finer ones, they'll rip through this steel easily, which leaves the edge very toothy, if not downright ragged. I've been in the habit of at least fine-tuning those edges on wet/dry sandpaper (400 grit or higher), which is a bit less aggressive, and will do a better job of cleaning up the ragged burrs left by the diamond. More often than not, I don't even use diamond for 420HC anymore. After the sandpaper, I strop on green compound on leather (this steel really responds well to it), followed by bare leather. I personally prefer using sueded leather for this (both with compound and bare, on the inside face of my leather belt).


David
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I'll try the sand paper and green compound David. I have a two sided suede stop with nothing on either side so time to use it I guess. I also have piece of 1/4 glass plate that I could put the sandpaper on, sound good?
David
 
SC_Dave said:
Plates are broken in but I think I could use less pressure. Thanks.



I'll try the sand paper and green compound David. I have a two sided suede stop with nothing on either side so time to use it I guess. I also have piece of 1/4 glass plate that I could put the sandpaper on, sound good?
David
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That's exactly how I've been using the sandpaper, with edge-trailing strokes & light pressure for cleaning up the burrs. The pressure is what creates most burr issues in the first place, so you want to keep it light. Basically identical to stropping, but at more aggressive grit. I like how it works. Even better if the paper is firmly seated/stuck to the glass. Some temporary (repositionable) adhesive works well for that, and makes it perform almost like a SiC stone. If you don't have the adhesive, some binder clips or painter's tape will hold it down too.


David
 
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I find the two grits on the Sharpmaker and pocket stones are about perfect for my Bucks. Then again, I don't look at my edges through a loupe.
 
Obsessed with Edges said:
420HC has a strong tendency to leave tenacious burrs on the edge, which I'm sure is behind the 'hairy' cutting you mention. Chipping isn't likely at all; more likely the 'chips' you see are the deep gouges left by the diamond.
David
Click to expand...
David, This steel's grain size could be afoot in this equation as well. Agreed, when sharpening this steel on a diamond stone it leaves micro serrations. However, I've noticed sharpening it on a Norton fine India leaves a much smoother edge. Dittos for D2. DM
 
David Martin said:
David, This steel's grain size could be afoot in this equation as well. Agreed, when sharpening this steel on a diamond stone it leaves micro serrations. However, I've noticed sharpening it on a Norton fine India leaves a much smoother edge. Dittos for D2. DM
Click to expand...

I still don't have an India yet, but I'll likely get one sometime. Wouldn't mind trying one out. Been pondering that quite a bit lately, in fact. :)

I haven't had too many worries about 420HC's grain size. I've noticed it'll take a super-fine edge if approached gently, and I think it may've been the first steel with which I produced a tree-topping shaving edge (it was a Case folder). D2 gets there as well (to a fine and/or polished edge), but takes a LOT longer, again while going about it very gently. I do think with D2, a lot of time has to be taken to file/abrade it's (purported) large carbides down to a thin apex, as opposed to tearing them out with a coarser grit. I keep tweaking the edges on a couple of Queen folders in D2, and every time I go back to them, they get a little finer. I thought I'd found the limit with the steel some time back, but it continues to surprise me.


David
 
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I much prefer waterstones for 420hc, produces a very nice and very sharp edge with minimal effort.
 
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