Is there a way to reduce single bevel weight difference?

D

DavidL41

Joined
Oct 12, 2014
Messages
160
Cutting with a single bevel kiridashi on leather the cut tends to wander the direction of the bevel is going. Symmetrical bevel cuts normally. I am guessing this is normal. The kiridashi is the suitable knife in this situation because of its flat bevel to trace around ruler, plus easier to find 90 degrees.

First question. Is this normal for the cut to move direction of the bevel on a vertical cut?

Would adding metal the thickness of the kiridashi on the flat bevel even out the pressure or does the cut move off vertical because of its single bevel?
 
The blade will always do that, blades with a Ura do it less but it still happens. Whenever the geometry is unequal the edge will steer.
 
I believe the knife is for right handers. For leather the bevel has to be down to skive with single bevel. Flip the knife over and it is right handed. Same goes with wood, although bevel up can be done too. It does look better in pictures this way so its hard to tell.

Is it possible to get a hollow grind to have an ultra thin edge for 5mm or is this too difficult to grind. Durabilty is not an factor
 
Might try narrowing the edge angle a bit, taking the bevelled side more acute relative to the flat back of the blade. The 'steering' caused by the asymmetry will be reduced at a lower angle. I've noticed that the chisel-ground blade on my Leatherman Micra cuts pretty much dead-straight when slicing through paper & such, and I think that's got a lot to do with the thin blade stock and relatively acute edge grind. At a more obtuse angle, the effect of the bevel will be greater in adding resistance to the path of the cut on one side, which will try to steer the blade into the plane of the bevel on that side.


David
 
Last edited:
The more shallow the cut the less steering you will have. If at all possible, you can angle the knife into the cut and this will also reduce the tendency to steer.
 
My approach would be similar to David/OWE. Change chisel bevel to 8*, add a micro 15* bevel to the back/flat side. Basically, try to counter/minimize steering from chisel with a micro. Of course it's a balancing act which depend on material height/depth & density & granularity. e.g. push cut a 1" tall block of cheese vs 5/32" thick leather, where chees steer more because of depth + uniformly high density + ultra small grain.
 
I did notice that my thinner bevel kiridashi has less steer. Still too much steer. I can use it for skiving regardless.

The problem with a micro bevel is that it will catch on the edge of the template unless it is very thin.

I may go another route getting a thin thickness kiridashi dual bevel but have a very tall and thin hollow grind. If the profile can match the thinness of a olfa utility knife or scalpel it would cut straight enough, it would need to be a constant thinness. Is it possible to go that thin on hollow ground blades?
 
DavidL41 said:
I did notice that my thinner bevel kiridashi has less steer. Still too much steer. I can use it for skiving regardless.

The problem with a micro bevel is that it will catch on the edge of the template unless it is very thin.

I may go another route getting a thin thickness kiridashi dual bevel but have a very tall and thin hollow grind. If the profile can match the thinness of a olfa utility knife or scalpel it would cut straight enough, it would need to be a constant thinness. Is it possible to go that thin on hollow ground blades?
Click to expand...

I don't see why not. The hollow-ground sheepsfoot on my Case 6375 CV stockman is the thinnest blade I've ever seen (primary grind), and I've subsequently taken the edge grind even thinner than the factory's original grind. It's the most effortless slicer I've got. The '75-pattern's sheepfoot is also a pretty wide (tall) blade profile, so the thinness extends high above the edge grind. It's definitely delicate at the edge and at the tip, so it needs pretty regular touch-ups (this is dead simple on a sheepsfoot profile, as a bonus). But I don't think there'll be a problem finding other hollow-ground blades thin enough and durable enough to do the job.


David
 
Thanks.

One quick question.

Sharpening rod or curved waterstone? Can a sharpening rod effectively sharpen a hollow grind or does it need to have a certain shape.
 
DavidL41 said:
Thanks.

One quick question.

Sharpening rod or curved waterstone? Can a sharpening rod effectively sharpen a hollow grind or does it need to have a certain shape.
Click to expand...

Any stone or tool that works on other grinds (flat, convex, etc) will work with a hollow grind. The edge bevels on hollow-ground knives are no different than any other; it's just the primary grind above the edge bevels that's hollow. In a couple of aspects, sharpening hollow-ground blades is easier than with most other grinds, as the steel behind the edge is usually thinner (edges will thin out and sharpen MUCH quicker), and the 'hollow' above the edge makes it more difficult to accidentally scratch the upper portions of the blade while sharpening.

The only caution I'd mention with a sharpening rod is, be sure to use it very lightly; the round profile of the rod will focus pressure against the edge, making it easier to roll or burr the edge if pressure is too heavy.


David
 
I was under the impression a rounded profile stone would be used on hollow grind. Wouldnt the hollow grind belly above the edge not contact the stone?
 
Last edited:
DavidL41 said:
I was under the impression a rounded profile stone would be used on hollow grind. Wouldnt the hollow grind belly above the edge not contact the stone?
Click to expand...

yes, the hollow in hollow grind usually doesn't touch the stone when you're sharpening,
thats one of the benefits, you lay the knife flat against the stone and just rub
like a straight razor, the knife is its own angle guide
after many many many ... sharpenings you will eventually have a flat ground knife
at that point you can regrind/reprofile it on a "wheel" and make it hollow again
 
DavidL41 said:
I was under the impression a rounded profile stone would be used on hollow grind. Wouldnt the hollow grind belly above the edge not contact the stone?
Click to expand...

I think bucketstove covered it. On most any hollow grind blade, the steel very near the edge (within the typical width of most edge bevels) would still essentially be 'flat', so there's really no circumstance that I know of that would prevent enough of the edge from contacting the stone, if that's what you're concerned about. And even if it initially was that extreme near the edge, a new bevel created at the edge will widen (& flatten) as you continue to work it, as with any other edge grind. The pic below is of a knife that's got the most extreme hollow grind of any I own. Very thin near the edge, but widening to 3/16" thickness at the spine. I used a Lansky (w/flat hones) to apply the edge shown on that knife, and it worked out great. No worries. :)

As bucketstove mentioned, one can just lay a hollow grind blade flush to a stone if desired. I don't normally go that low in angle, but a hollow grind straight razor is ordinarily sharpened that way.


David
 
Last edited:
You must log in or register to reply here.
Back
Top