Common materials being cut

Blueeyeddevil said:
I know this is a somewhat off topic, but Moine's avatar character looks incredibly like some sort of mutated "Sharp" Phil. :
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Nope. It's me that's mutated on the pic.

David
 
Cliff Stamp said:
For metal cutting you want a very hard edge to resist deforming and high wear resistance, hardness tends to be more important in the short term, especially with very thin knife edges as they deform more so than wear.
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Agreed. I should have put it that way : no general use knife will come out of that shaving sharp.

I wouldn't want a 65 RC M2 blade on a blade that'd be used to chop or baton.

I think general porpose blade designing is some kind of a fuzzy logic problem.

Say you use the blade, on average, for 65% wood chopping, 8% wood carving, 7% hide scraping and cutting, 12% meat/flesh cutting, 1% metal cutting, 2% bone cutting, and 5% misc... Each of those tasks should "attract" the morphing of the blade towards it's own specialized shape, geometry, steel choice, heat treatment, etc.

The deal is to put priority tasks first. For me : chopping, wood carving, field-dress/butcher (cut hide, chop bone, cut precisely where I want and not puncture anything stupidly)... So I like a high flat grind and wide blade, with a THIN convex sec. bevel, not too hard a steel (58 or so), with a clip or spear point (no sharpened false edge) and plenty of belly.

I think Razorback's blades are VERY close to what I need in the field. My only question would be how thick his sec. convex bevels are... I like them thin to get better cutting perf., even if I have to sacrifice hardness a bit to avoid chipping.

Cheers,

David
 
Moine said:
Agreed. I should have put it that way : no general use knife will come out of that shaving sharp.

I wouldn't want a 65 RC M2 blade on a blade that'd be used to chop or baton.

I think general porpose blade designing is some kind of a fuzzy logic problem.

Say you use the blade, on average, for 65% wood chopping, 8% wood carving, 7% hide scraping and cutting, 12% meat/flesh cutting, 1% metal cutting, 2% bone cutting, and 5% misc... Each of those tasks should "attract" the morphing of the blade towards it's own specialized shape, geometry, steel choice, heat treatment, etc.

The deal is to put priority tasks first. For me : chopping, wood carving, field-dress/butcher (cut hide, chop bone, cut precisely where I want and not puncture anything stupidly)... So I like a high flat grind and wide blade, with a THIN convex sec. bevel, not too hard a steel (58 or so), with a clip or spear point (no sharpened false edge) and plenty of belly.

I think Razorback's blades are VERY close to what I need in the field. My only question would be how thick his sec. convex bevels are... I like them thin to get better cutting perf., even if I have to sacrifice hardness a bit to avoid chipping.

Cheers,

David
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David, to answer your question, I convex to almost a zero edge, I have a very slight secondary bevel. I'm right at 0.025 to 0.030 at the edge. Some may feel this is too thick, but I have not had any problem doing woodcraft and game work with this edge. Now if you need a super thin fine edge, a thinly ground flat or hollow grind would be in order. I do not want to sacrifice edge strength, this is why I choose this type of grind and edge.
Scott
edit to add: I measured my Randall model 15 with a hollow grind and it was at 0.025 at the edge.
 
Moine said:
I wouldn't want a 65 RC M2 blade on a blade that'd be used to chop or baton.
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No, that would not be overly productive, you could probably handle clean grain readily, but twisted wood or knots would be problematic unless you wanted to take a hundred hits to split a round.

I tend to favor toughness and strength in those class of blades, wear resistance is ince if you get it for free, but I would not trade much for it. Just get a simple tough steel like L6.

In regards to "softening steels" for toughness, generally choose another steel, instead. You can make anything tough enough impact wise if you leave it soft, but you lose strength.

-Cliff
 
Scott,

That answers my question very well ;) -- Must cut well, yet be tough.

Thanks. Get ready to quit your day job now ;)

David
 
Thanks David. ;) I feel all grinds and edges have their place, but I have grown so fond of the convex edge and grind that's all I feel I need. For kitchen use, I like 1/8" or 1/16" thick blade with this grind and edge. My wife keeps bugging me to make her a utility kitchen knife with D2, but I tell her customer orders first. :D
Scott
 
Razorback - Knives said:
My wife keeps bugging me to make her a utility kitchen knife with D2, but I tell her customer orders first. :D
Scott
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Carefull, she might put you on the couch!

:D
 
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