Let's Talk Re-Profiling Free Hand...

Eli Chaps

Eli Chaps

Joined
Apr 20, 2018
Messages
4,458
Hello Sharpeners,

So admittedly, the bulk of my bona fide re-profiling has been done with the KME. In this discussion I'm defining "re-profling" as an intentional increase or decrease of the sharpened bevel angle. I don't mean re-profiling in the sense of getting a factory grind to match our natural free hand grind.

Like many, I like to use a marker to help direct my sharpening, especially on new/semi-new knives. Real quick for those who may not know, if you color the bevel with a marker and then slide the knife over the stone it can help indicate your angle. If you're taking more off the shoulder of the bevel, you're low (leaning the spine too far into the stone). If you're taking more off the very edge, you're high (leaning the spine too far off the stone).

A while back I bought a $30 Dexter Russell "Vegetable Clever" to both see how I like the blade shape but maybe even more so to play with thinning blade thickness and messing with bevels. I don't have cash to just toss around but at $30 it was easy enough to swallow. Great knife by the way that I'm having a lot of fun with, even if I didn't mess around with the edge. But I have been. Now, I knew I was going to scratch this thing up experimenting so don't flog me for it. I did a little grinding at around 5 degrees on a Norton Course Crystolon and Fine India to play with thinning. I know, scratches. But it showed me a ton and did accomplish what I was after. Don't have my calipers right now but I did thin out the edge.

I have started to look at laying the bevel back a little but because I also thinned it, I'm not sure it's a direct relation.

See, I have this Yaxell Asian Fire gyuto in BD1N that @DeadboxHero keeps telling me to lay back and I'm thinking I want to. It's at a verified 15dps and I think I'd like to end up at somewhere around 10-12dps.

This knife is 5x the cost of the DR so ya know, I'm a little more sensitive to scratching it up. :)

IMG_20190415_163924390_zpsd7bifaze_edit_1555373511511_zpsvbaxi9xc.jpg

What I'm thinking is, I color the bevel and get it to be just taking more off the shoulder and then continue to grind until I apex. A little at time. Maybe it takes a few sharpenings over time.

Is that what you folks do or do you just go for it and drop four or five degrees at a whack? Do you just lay the spine back a bit and grind until you have a burr?

Am I over thinking this? :D

Like I said, I can smooth out things on the DR when I get around to it, but I'd just as soon not start that way on the Yaxell.

As always, thanks in advance.
 
Why are you avoiding the guided system if you also want to avoid scratches? If you are using this as a learning experience why not keep working on cheaper knives for a while?
 
Mr.Wizard said:
Why are you avoiding the guided system if you also want to avoid scratches? If you are using this as a learning experience why not keep working on cheaper knives for a while?
Click to expand...

Fair question. I can't lay the KME back much more. Yes, I can flip the carrier over and mess around with that but it's also a slow process, especially on a knife this size.

Not sure I'm going to kick the training wheels off yet but I'm wanting to learn so that I can. I have some other lower cost knives I can play with but the fundamentals of the inquiry would be the same.

:)
 
Especially for the high vanadium blades such as S110V I reprofile just as you describe; marker on the bevel and then take it free hand to my 10" DMT Extra Coarse. It does the job in no time.

I get close to the apex but do not go all the way to the edge; no reason to.
Then I put the blade on my Edge Pro and refine the bevel and take the new angle all the way to the edge.

This has worked very well for me.
You can always tape the sides of the blade to help prevent scratching it up while free handing and reprofiling.

The long stone really helps get the job done. Surface feet per minute and all like that.
 
Yes, I see that is a problem with clamp systems. There are several kinds of reprofiling and it may be helpful to distinguish them.
  1. lower the edge bevel angle
  2. cut a low-angle relief bevel behind the edge bevel
  3. thin the blade grind
My thinking: Type 1 can be done guided or freehand. Type 2 I would only attempt on a guided system as freehand extraordinary control would be needed to avoid scratching the face of the blade. Type 3 is a freehand (or custom grinding jig I suppose) operation and will require refinishing the blade with progressively finer abrasive.
 
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Mr.Wizard said:
Yes, I see that is a problem with clamp systems. There are several kinds of reprofiling and it may be helpful to distinguish them.
  1. lower the edge bevel angle
  2. cut a low-angle relief bevel behind the edge bevel
  3. thin the blade grind
My thinking: Type 1 can be done guided or freehand. Type 2 I would only attempt on a guided system as extreme hand control would be needed to avoid scratching the face of the blade. Type 3 is a freehand operation (or custom grinding jig I suppose) and will require refinishing the blade with progressively finer abrasive.
Click to expand...

Just #1 in this instance. I reckon I just want to be sure I'm laying it back and am consistent. It's easy to follow an existing bevel but altering it is going out of bounds if you will. Suppose the marker should provide sufficient guidance though.

Now that I think on it, maybe I'm looking for more of a pep talk than technical input...? :D
 
I think it’s more difficult to lower the angle than increase it. To effectively lower the angle, one has to grind off more metal. This can be done over time, i.e. every sharpening spends some lowering like recommended by @Obsessed with Edges . Increasing angle is simpler. Just add microbevel until edge is no longer damaged during use. This is assuming no half moon shape chipping occurs.

I usually try to do the reprofiling/thinning at one go, because I don’t use it to warrant sharpening often so it may never come to fully apexed. If I want to enjoy the thin angle, it has to be done purposefully until apexed. It also will allow me to touch up more effectively because of the wider bevel face makes it easier to detect when it’s flush with the stone surface.

If one doesn’t have good angle control, creating a sharpening wedge with the desired angle (3D printed, wood, etc) should help avoiding scratches higher above the bevel. Earlier when my angle control was still bad, I couldn’t finish it in one go, so have to break it into several sessions and it scratches the side like crazy :(.

From my experience, thinning down factory bevel will usually increase the BET because the bevel will end up higher in the primary grind.

Edit: so many good responses already when I was thinking & typing :).

The problem with marker when thinning the bevel is that you cannot use it to ensure consistent angle because basically you’re starting a new bevel with the width of 0 at the shoulder. It only works for trying to match the current bevel.
I suggest use an angle wedge, or use geometry to calculate how high the spine at the heel should be from the stone to get 10°, and wing it from there. Start with 10° and the free hand wobble will get you to 12° or so.

Very nice knife BTW :thumbsup: it should not be a huge problem as usually it’s thin so reprofiling shouldn’t take very long with coarse stone.
 
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Chris "Anagarika" said:
...

I usually try to do the reprofiling/thinning at one go, because I don’t use it to warrant sharpening often so it may never come to fully apexed. If I want to enjoy the thin angle, it has to be done purposefully until apexed. It also will allow me to touch up more effectively because of the wider bevel face makes it easier to detect when it’s flush with the stone surface.

...
Click to expand...

This is what I was thinking as well.
 
Eli Chaps said:
Just #1 in this instance.
Click to expand...

And you're still maxed out on the KME? That's unfortunate. I am not familiar with the system but can you fit it with a longer clamp to lower the angle? I saved a couple of photos of improvised solutions; I cannot remember the authorship to give credit, but I'll edit this to add it if I find the original.

I am going to be the anti-pep-talker: that is a beautiful knife and I think you should either practice until you are confident that you won't scratch it, OR be prepared to put a hand rubbed finish on it which will be a lot of work, but also rewarding assuming you like that look.

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Nothing wrong with a voice of reason for sure my friend and much appreciated!

On the KME, with a blade of this design, in the standard configuration, I'm about as low as I can go. If I got it out and gave things a good look I might be able to get a touch lower. That said, some folks flip the rod guide upside down and that allows for lower angles. I'm considering this and might well have a go at it.

I'm in no rush to do anything right now. Just soliciting the feedback of this generous community.

The Yaxell is a fine knife and as C Chris "Anagarika" said, it is already comparably thin.
 
If I'm going to thin it, I thin it to a fresh apex. I might stop just shy of a new burr, but that depends on the quality of the existing grind. If they'e even I'll stop just shy, if they aren't I forge ahead and deal with the burr later.

First I take a good look a the whole blade grind, esp around the bolster and plunge line. Many knives can only be thinned so much without a regrind of the primary, so is a good idea to know what you can get away with before you trash anything.

I have an angle cube and one of those magnetic guides for running conduit, although I can pretty reliably freehand between 26 and 28 inclusive with no guide.

Next step is to see if the existing grinds are symmetrical and even. If they aren't, I'm going to fix them at the same time. A close look at the tip viewed dead on can tell you a lot. Also now is the time to take stock of the warps, twists etc.

After that it's full speed ahead, the only remaining consideration to be what stones I'm going to use based on steel type. I also flip sides often to match the bevel width as much as possible with whatever warps are present.
 
Thanks HeavyHanded HeavyHanded . The bevel on that guy is a touch wider on one side than the other so that is something that I'm conscious of with every sharpening as it is now. I try to spend a little more time on the "thin" side each time I sharpen it and the bevel is starting to even out.

I'm not sure I'm going to dive into this any time soon. Could be I take M Mr.Wizard 's advice and keep practicing some more. I suppose I should clean up the DR before I do anything else. :)
 
Very good. If the regrind needs to remove a lot of metal, I'll take it to my JUM-3 the coarse side. Set the bevel and remove the burr then on to the fine side, 280 grit. On this I don't want to change anything, just refine it, correct any little thing and get all the burr off. I work
a little harder on this grit to leave a very clean edge. DM
 
Eli Chaps Eli Chaps
On good knives, like your Yaxell, remember to take your time and focus on stroke consistency.

I just finished reprofiling my XHP Broken Skull. Couldn’t find time/space to use waterstone (like I mentioned), so I resorted to the DMD 400 & 1000, with oil and wood grain to give better feedback. It went ok until my left hand angle dropped unconsciously, resulting in scratched above the bevel. That happened when I tried to rush the job instead of paying attention to the stroke.

Nowadays when I do pay attention, I always came up with rather flat bevel although not as good as HeavyHanded HeavyHanded in 1° variations, but rarely scratch above the bevel. The worst is the bevel is wider because of the wobble about 2-3° (eyeballing).
 
There are a bunch of keys to doing this reliably.

For me, a big one is really locking the knife/tool handle into your grip. You will have to make adjustments at the wrist to accommodate the angle as it moves, but if you have added shifting in the hand it just adds another level of slop.

I've mentioned this many times over the years and demo'd in the chisel video but only explained once, a quick bump off the shoulder as you work is a great way to feel out the angle and recalibrate on the fly.

On better stones, you can actually feel when you've ground a new apex because the edge will suddenly have more drag - not all along at the same time, but it will just start to feel sluggish on the stone. If you bounce off the shoulder and come back up, and it still has drag you don't even need to look, you're done. Give it a quick "three finger sticky" and rub fingers perpendicular to the edge from spine off the edge.

In this way you can reset a bevel entirely without using your eyes. Some of this stuff I really dialed in on my guided rig as I could sit back and pay 100% attention to the feel of the blade on the stone and not have to concentrate on grip or angle adjustment. Then was able to apply it back to 100% freehand.
 
Ah yes, the bump in the shoulder. Unless it’s the 2nd shoulder accidentally created by mistake like what I did :oops:

And the drag of apex :thumbsup:. Very reliable indicator. More obvious in higher grit (i.e. DMT 600 and above) but it’s there nevertheless.

Another reason I like to thin the angle. It has better flat feedback as the bevel is wider.
 
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