Overthinking sharpness

Obsessed with Edges said:
FWIW, tip grinds on so many knives are often thicker geometrically as the edge grind sweeps up and meets with the usually thicker steel near the spine. Even when the apex at the tip is fairly crisp, the tip will still seem to want something more for sharpness. Most factory grinds will attempt to keep the bevel widths uniform all the way from the heel to the tip, as it looks better to most buyers. So, with the bevel width being the same at the thicker tip, the edge angle there will often be much wider (more obtuse).

You can bring the tip sharpness up to match the rest of the edge by grinding the edge bevels near the tip more acutely than factory. The trade-off will be, in doing this, the edge bevels in the thicker steel near the tip will be noticeably wider, sometimes MUCH wider. For appearance's sake, it may look odd to some. But it can still be gradually blended into the overall edge grind and the tip sharpness will improve dramatically. With my own knives, I've opted to get that extra sharpness all the way out to the tip, and I can live with the gradually widening bevels approaching the tip.

Edited to add:
And because of the thicker steel and the wider edge angle near the tip, it's very common to come up a bit short of full apex when attempting to sharpen the tip at the same held angle as for the rest of the edge. It usually takes much, much longer to fully apex near the tip under these circumstances. Examining the edge under high magnification and under good light will show if the edge is fully apexed or not.
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I was just having this exact problem with my Case single blade sowbelly in CV steel. After reading this I went back and worked on just the part of the blade from where the upsweep starts to the tip. Only took a few minutes to get it cutting same as the rest of the blade. Thanks!
 
Ace Rimmer said:
I was just having this exact problem with my Case single blade sowbelly in CV steel. After reading this I went back and worked on just the part of the blade from where the upsweep starts to the tip. Only took a few minutes to get it cutting same as the rest of the blade. Thanks!
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One of the knives I'd pictured in mind when describing this was my Case 6375 CV stockman; specifically the clip blade. It's pictured below. I reground the same portion of that blade from the forward portion of the 'belly' to the tip. It does show some widening of the bevel as compared to the rest of the edge grind, which I'd also taken thinner and considerably more acute in geometry, as can be seen below. In terms of sharpness at and near the tip, it's where I like it to be now. Doing this is almost standard for me anymore, when I acquire a new knife. It's one of several ways I 'make it my own'.
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The True North said:
True. Recurve and hawkbill knives are essentially impossible to sharpen without Spyderco's triangular rods.
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No wonder I’m always so impatient. I’ve been waiting decades for somebody to invent the extra smooth round file, or the knob-and-tube ceramic insulator, or wet/dry sandpaper around a tapered dowel…

ETA: that’s a sweet ‘75, David. Nice regrind, and I love the patina. You inspire me to try the same on a couple of my Schrade 858s.

Parker
 
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I only somewhat recently started reprofiling knives manually on stones, and I quickly learned that I hate sharpening sodbusters and spey blades because of the upswept tips, much harder to maintain a consistent angle all the way to the tip.

I usually reprofile on a flat stone at less than 30 degrees and then put a 40 degree microbevel on with a Sharpmaker. I still can't get nearly as clean an edge on the tips of upswept blades, but as long as you establish an edge (not popping hairs like a clean edge off of 325 grit, but at least shaving hairs and easily catching your nail) a microbevel on rods/a fixed angle system will still end up at a more than acceptable place (maybe a bit of extra time to refine the tip but you don't need to remove much of the freehand edge with a microbevel/small secondary edge at a higher angle)
 
catspa said:
No wonder I’m always so impatient. I’ve been waiting decades for somebody to invent the extra smooth round file, or the knob-and-tube ceramic insulator, or wet/dry sandpaper around a tapered dowel…

ETA: that’s a sweet ‘75, David. Nice regrind, and I love the patina. You inspire me to try the same on a couple of my Schrade 858s.

Parker
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Yep those work-arounds exist.

The fact remains, the triangular rods are far superior and are the real solution to the problem.
 
Okay.

Kinda reminds me of convex ground salon shears. They were and are marketed as being sharper and smoother cutting than bevel ground shears, which is true (although their edge geometry is more fragile).

Some companies sell some ungodly expensive machines for convex sharpening, others like Wolff offer less expensive bolt-on accessories for their standard scissor grinders (but you still have to buy special abrasives). I suppose if a person sharpened 20 pairs a day, they could easily justify expensive tooling. I can’t, however, and so I use much simpler low-tech methods to serve my few clients who prefer convex shears. I meet or exceed the factory sharpness, perhaps more slowly and awkwardly than necessary, and the hairdressers are happy.

Meanwhile, there are others who have been cutting hair for decades using bevel ground scissors, and actually dislike convex shears when I loan them a pair. Maybe they learned before the convex ones were popular/available. But their function just doesn’t justify the extra expense.

Now watch, when I get some triangular rods, I’ll be shouting from the housetops how good they are. But I won’t be telling anybody who’s been successfully doing something for years that it’s impossible.

ETA: I’m not mad at you or trying to be snarky, just have different experiences that led me to different methods.

Parker
 
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The True North said:
Yep those work-arounds exist.

The fact remains, the triangular rods are far superior and are the real solution to the problem.
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and one or two fit so easily in my man purse er . . . satchel , that I always have it with me .
Often I'm on the bike so not like I have a tool box in the truck bed .
 
Jared Leland said:
Is this a situation where i should Just use my knives and quit overthinking overall complete perfect sharpness?
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wellll . . . good enough is good enough
but
better is better
Reminds me of a Nevil Shute book I read .
Main character is hitching to the other side of the world to save a little girl's "trust fund" after her parents are killed in a hurricane .
He is traveling by tips from people who took him a ways of who he might talk to next .
One guy that takes him on a sail boat he made is the son of a dead ship builder . The son is mentally challenged but knows his way around making boats and sailing them long distance on the ocean.

Main character is looking at a model of the boat they are sailing on .
He says : Why did you make it like that ? Wasn't that more difficult ? It IS NICE LOOKING .
The challenged young boat dude says : I made it like that because if I hadn't then every time I would have looked at it it would have made me mad . 😠

Better edges can make you smile .
 
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catspa said:
No wonder I’m always so impatient. I’ve been waiting decades for somebody to invent the extra smooth round file, or the knob-and-tube ceramic insulator, or wet/dry sandpaper around a tapered dowel…

ETA: that’s a sweet ‘75, David. Nice regrind, and I love the patina. You inspire me to try the same on a couple of my Schrade 858s.

Parker
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Wet dry is always a good go to but round stones go way back, slip stones, scythe stones and others for about any job imaginable.
 
I don’t know how sharp you are capable of getting them but I know sometimes I am tempted to get my knives as sharp as possible which usually means effortlessly shaving, however if you get it that sharp you will roll your edge very quickly
 
You raise a valid point, each knife has its limit of edge geometry after which you start losing durability. There’s a sweet spot, but it often takes a while to find it.

Parker
 
I have a hard time when customers come in wanting knife sharpened, the perfectionist side of me wants to get the knives as sharp as possible but I realize that is probably not best for the customer as they will have to have it sharpened more often
 
Also it depends on your angles, if you want a slicier edge you want to lower the degrees per side but if you want it to last longer, a higher dps will help but I am probably getting off topic
 
Old Biker said:
Still not true. There are other stones designed to sharpen recurved blades. Just because something is your favorite, doesn't make it the only option, or the best option for everyone.

O.B.
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The triangular stones are objectively the best option for recurves and hawkbills.
 
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