# How would you sharpen X?



## crockerculinary (Jan 29, 2022)

So I was thinking about sharpening while sharpening, as I often do, (a Victorinox fibrox in this case, probably my 30th this week) and had an interesting idea for a thread.

As most everybody here knows, there is no “best” way to sharpen a knife. There is good and there is bad, but not really a best. You can sharpen one knife many different ways with different results and different positives and negatives for each approach.

There are obviously “better” and wiser approaches to different knives, that take the most important variables into account- steel type, edge retention and strength, cutting ability, how someone cuts and what specific tasks, how much time it takes, etc., and some might say there is a narrower range of “optimum” choices when it comes to navigating all those variables.

So this led me to think if I was to ask 10 different sharpeners how they would sharpen a specific knife, would I get 10 different answers?

That takes me to the question and point of this thread-

Lets say you were given a Fibrox to sharpen. (I’m choosing Fibrox because that is probably the most common knife I see coming from professional kitchens and cooks, and I think we all know it enough to make this a good choice, although I would also be interested in doing this same experiment with other common knives) so without any other information about the user or it’s use, how would you approach it for “optimum” results?
What angle, what finishing grit, what medium, would you strop, convex, or any other variables that you think are important to get the best out of the knife.

What would you do to get the best out of the knife, for whatever you think are the optimum results? And if you have the time, why?


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## ModRQC (Jan 29, 2022)

Have a few Fibrox/Rosewood.

The parer was always handled differently so let's skip it - but usually this one gets a coarse edge and being barely thicker than cereal box cardbord to start with, so far has always just been more touched up than really sharpened. 

For a 6" petty to a Santoku to both 8" and 10" Chef, I cut a relief bevel at the lowest angle that makes sense. Keep it as convex as possible. Sharpen at a reasonable angle for steel. Say 20 dps. Usually a full sharpening involves something like Nano 200, SG500/SP1K, SP2K.

Will do something like that with most western knives, but they don't all come nice like brand new Victos, so it really depends.


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## HumbleHomeCook (Jan 29, 2022)

All the sharpening will be freehand so it's next to impossible to know exactly what angle and I can only approximate based off experience and comparing to jigged systems.

For someone else and assuming nothing's messed up, I'm going to go pretty generic and just use the factory angle as the guide. Mood depending, I'd use either a soft Arkansas or Norton Fine India or maybe a Shapton Glass 500. Likely I'd start on the India and then finish on soft Ark, using oil. Strop on suede with green CrO compound for edge refinement and then some strop passes on bare cardboard.

For me, I take the entire primary grind to some sand paper, working up to about 400grit with a focus on the edge bevel shoulders. Then I'd probably go to a Norton Coarse Crystolon and lower the edge bevel by a couple degrees. Nothing too much, maybe in the 17dps range. Then I'd finish pretty much as above.


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## Benuser (Jan 29, 2022)

It's a few years ago I used to sharpen Fibrox chefs' OOTB quite frequently, and first thing I did was removing the shoulders with the coarsest stone I had in those days, a Chosera 400. I was quite surprised by the high angle of the edge, far above 20⁰ per side, but basically kept it like that, and deburred with the coarse side of a green ScotchBrite sponge.


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## tostadas (Jan 29, 2022)

With no other info given other than here's a Fibrox to sharpen,

-Norton Crystolon Coarse (only if needed, otherwise skip)
-Shapton Pro 1k to set bevels at roughly 15deg ea, finish with light edge leading strokes after debur
-Finish on Shapton Pro 2k
-Strop on jeans

On my own personal Victorinox, I go a bit more aggressive on the bevel angle, probably closer to 12deg and finish on an Aoto, which is a bit finer than the SP2k. But if it's for a friend/family, I'll lean toward more conservative. A side note, I really like the Victorinox steel and feel like it sharpens up and holds its edge better than most other soft stainless such as Wusthof, Henckels, or the garbage Kitchenaid/Cuisinart.


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## tcmx3 (Jan 29, 2022)

crockerculinary said:


> Lets say you were given a Fibrox to sharpen. (I’m choosing Fibrox because that is probably the most common knife I see coming from professional kitchens and cooks, and I think we all know it enough to make this a good choice, although I would also be interested in doing this same experiment with other common knives) so without any other information about the user or it’s use, how would you approach it for “optimum” results?
> What angle, what finishing grit, what medium, would you strop, convex, or any other variables that you think are important to get the best out of the knife.



nominally 22 DPS, but hand sharpened
chosera 1k or SG500, whichever was closer at hand
strop, I use a strop with 1 micron diamond BUT I tend to let it get kind of low on the charging so it cuts really slow
if it's for a friend (and I would only sharpen for a friend), I would include a shi.han edge guard because the thing that would help most folks keep their knife sharp the longest (besides getting a better cutting board), is not chucking it in the drawer ****ing raw


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## ModRQC (Jan 29, 2022)

tostadas said:


> With no other info given other than here's a Fibrox to sharpen,
> 
> -Norton Crystolon Coarse (only if needed, otherwise skip)
> -Shapton Pro 1k to set bevels at roughly 15deg ea, finish with light edge leading strokes after debur
> ...



Stropping on jeans I used to do that a lot. Nowadays used denim as it sounds more high end classy stropping.

No really I just don’t anymore. I go trough three stones ensuring I won’t have to strop anything if I worked well.

I also like their SS. It’s nothing much but they’ve got a pretty foolproof recipe of 1.4110 and HT that lends to easy maintenance, rods included. They keep a reasonable edge reasonably well.


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## HumbleHomeCook (Jan 29, 2022)

Cut the leg off an old worn out pair of pants. Stuff a length (8"-12") of 2x4 into it wrap tight. Works pretty well.


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## Troopah_Knives (Jan 29, 2022)

Probably pull out a 1k diamond stone as I've found I get less carbide pullout when I use them (although I haven't measured it by any objective metric). Shoot for like 20 DPS (erroring on the lower side) then strop with something fairly aggressive to add some convexity. Won't be the sharpest edge ever but frankly, 1.4110 probably dulls quickly due to rolling and fatigue cracks (as opposed to abrasion) so I'd say the extra stability is definitely a worthwhile trade.

As a side note: I really like the thread idea its interesting to see how people apply their knowledge to tackle a problem like this.


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## ModRQC (Jan 29, 2022)

Been there. Just try not using stropping anymore. Not always a win with these Victo but getting close enough now. Will use the palm of my hand to test and flip any clinging burr and edge lead on the stones. When any they usually shed away pretty fast. SP2K is a perfect stone to finish on and do that on with these.


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## ian (Jan 29, 2022)

With a Vic I would usually cut in a lowish angle relief bevel, then a more conservative primary bevel, assuming it’s really dull and/or thick bte, which it almost always is. Usually 1kish finish. Which stone depends on the mood I’m in, but Cho 800 or 1k, or JNS 1k, are favs at the moment. Minimal stropping at the end for removing burr remnants.


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## spaceconvoy (Jan 29, 2022)

For this type of steel I like to use a King Neo 800 to do the bulk of the work. Not sure if it's the SiC or the friability or both, but it's the best stone I've found for soft and gummy stainless. It may look like it's loading up with dark streaks of steel, but it keeps cutting if it's soaked (I don't see it as a splash-and-go stone, or at least not a good one). I don't mind if it takes more uninterrupted strokes, better than pausing to refresh a coarser stone that's less suited for stainless.

I just mentioned in another thread about how I like to finish softer stainless on an Ikarashi. Rather than chase down the last bit of burr on the Neo, I'll switch to the Ikarashi and slowly back off the pressure until I'm basically stropping on it. By that point there's a fine layer of dry sandy 'mud' on the surface that cleans up the edge and seems to remove the burr like magic.


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## M1k3 (Jan 29, 2022)

Depending on how bad it is, depends on what I'd do. But coming to me with lots of steeling and overall dull and some damage to the edge... The whole shebang to get back in business

Starting with a lowish angle, "relief bevel", Atoma 140 or Crystolon Coarse > SG 500 > SG 4k

Then followed by a regular sharpening angle, SG 500 > few swipes on Venev 800 > whatever handy strop is around. Usually my shirt sleeve.


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## Troopah_Knives (Jan 29, 2022)

M1k3 said:


> Depending on how bad it is, depends on what I'd do. But coming to me with lots of steeling and overall dull and some damage to the edge... The whole shebang to get back in business
> 
> Starting with a lowish angle, "relief bevel", Atoma 140 or Crystolon Coarse > SG 500 > SG 4k
> 
> Then followed by a regular sharpening angle, SG 500 > few swipes on Venev 800 > whatever handy strop is around. Usually my shirt sleeve.



I've never heard of the term "relief bevel" where can I go to learn more?


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## ian (Jan 29, 2022)

Troopah_Knives said:


> I've never heard of the term "relief bevel" where can I go to learn more?



Just means a secondary lower angle bevel, to make the knife a little thinner behind the edge. When I do it, it just looks like the bevel's a bit wide. Not making it so low angle that I need to refinish the blade or something.


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## ModRQC (Jan 29, 2022)

Troopah_Knives said:


> I've never heard of the term "relief bevel" where can I go to learn more?



If I can exemplify it in picture:







This my most "advanced" work on a Victo: 8" chef. 

My 10" resembles that but an older try at it that just does so well and has been lent to family so they could test against their own always rod-maintained Victo 10".

Here's the crude first edition of this...:






Pic taken tonight, and sandpaper finish very first work eons ago, relief and edge barely maintained from there. It's done good times since.

Funny we'd come to this example (congrats to OP for the really interesting thread) now. I used that petty just Thursday and decided it was time for a complete turnaround, nearing two years of faithful service. Gave it the best of my improved science on these Victo starting just tonight. To be finished tomorrow (sharpening) and documented into a post soon.

But a teaser pic:






It's not the same bevel as before. 

It's closing finishing touches but the relief has to be refined a bit. Final pre-cleaning/convexing/polishing work drew a burr in few strokes on Ouka. But it's now going straight sharpening, cutting an edge coarse to suit it well, then just refine the relief a bit going up SG500 and SP2K as I finish sharpening.

The old finish picture though is the basic idea, scratches involved probably but full sandpaper refinish quite not necessary. Nor going vertical Kasumi but does these well and MUCH quicker than sandpaper.

All this to be specified into the whole post. But roughly, 45 minutes on 4 stones, 5 minutes to flatten these afterwards, 5 minutes quick sandpaper blend and 5 good minutes wiping and googling it as the work progressed. Probably 20-25 minutes sharpening/refining left from there to get where I want to be. A lot of work if a friend's knife, but eons ago it didn't take so much time implementing this on the rough for a first on this one and transform behavior completely. 

Spent easily twice as much time perfecting the Rosewood 8" chef. Got to keep with value, and this petty is a barely 25$ CAD knife where I got it.


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## M1k3 (Jan 29, 2022)

Troopah_Knives said:


> I've never heard of the term "relief bevel" where can I go to learn more?


I don't remember where it came from. But it's thinning just behind the edge about 2-5mm or so, give or take depending on how much height has been lost, how much the knife has thickened at the edge. It helps out performance while not requiring a full on refinishing of the blade. Unless you are Gandalf the Great Stone Polisher.

Yeah, what @ian said!


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## ModRQC (Jan 29, 2022)

M1k3 said:


> I don't remember where it came from. But it's thinning just behind the edge about 2-5mm or so, give or take depending on how much height has been lost, how much the knife has thickened at the edge. It helps out performance while not requiring a full on refinishing of the blade. Unless you are Gandalf the Great Stone Polisher.
> 
> Yeah, what @ian said!



I consider my finishing work pretty straightfoward for a blade I use. Pretty rough in fact. You can always decide to reduce work to a minimum. However if I'm going to thin it and relief it a bit, what's getting the most of the stone progression used and just blend the work done. It's not 1 hour - more like barely 4 minutes per side on the first couple stones, 2-3 minutes per side on the finer ones, Could have stopped at Arashiyama 1K and just sharpen from there. I'm not showing the basics but how far one can take on the idea further in little time.

All this in or out, the blade gets to you much nicer than you leave it after such kind of work at any kind of zoom speed. I don't spend hours on a plank finishing these. I do as come as the best I discovered work adding as little to progs as I see fit. Ouka has nice works in vertical polishing. Smooth but not polish-catchy.

Not considering such work will last me another three years for sure with this one just touching up + couple sharpenings.

Sorry for not being lazy... or just wanting to expand on the idea.

Let's just all say we do it best without showing the work or owing much to the fact knives take work or look like **** or anywhere in between you decide to settle to save an hour of your life. Yet I won't spend several hours and use only stones and few tiny piece of sandpads. Considering I just barely settle above not looking like ****.


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## ModRQC (Jan 29, 2022)

Oh yeah and use Cerax/soft stones for these kind of things. You'll obiously spend decades on hard ceramics to even things out enough to get nice - lending you a sticky BTE geometry. Embrace scratches - it's full of it however nice it looks above, Like really full of it. The more polishing out some scratches. or a small overgrind, one spends, the more sticky that bevel will become. Vertical do best - yeah those Migaki are cheap but against 80% of finishes, they fare much better. Good luck with finding the other 20% as they come. Media blasted bevels are legion and seldom work best. Sanjo guys are quite willing offering horizontal finishes on cheap blades, but it just never really works. Even my Toyama suffered from it - but less than Wakui's or Mazaki's rougher iterations of it. 

Buy any S. Tanaka Migaki, or Sukenari, or Konosuke HD2.... to feel how it's done right. Then just make cheaper finishes end somewhere close - vertically. I'll say, however it looks. I don't care. It will feel right.


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## Benuser (Jan 30, 2022)

M1k3 said:


> I don't remember where it came from. But it's thinning just behind the edge about 2-5mm or so, give or take depending on how much height has been lost, how much the knife has thickened at the edge. It helps out performance while not requiring a full on refinishing of the blade. Unless you are Gandalf the Great Stone Polisher.
> 
> Yeah, what @ian said!


Chad Ward in An Edge in the Kitchen. It avoids the eternal confusion of primary and secondary bevels, used differently in different forums.


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## Leo Barr (Jan 30, 2022)

I sharpen professional visiting restaurants over a very large area all are regular bookings. All done on whetstones.

What I find with my sharpening is that I constantly evolve my approach almost every knife gives an opportunity to evolve (learn) which is why when asked on the whole for a method I do not like to give to much detail since to people who ask simply I have never stuck with one overall method or stone choice plus when I am sharpening my mind is chattering away considering so many points that if I was to try to convey that to someone it would mean very little.

I have at times been lead astray by what people have written or even shown in highly edited videos to the extent now I trust my own instinct & spontaneity -99% of sharpening is what works for you & is based on opportunities made by mistakes! 

With all knives I thin above the edge almost to the edge then put a micro bevel on top currently I will start at 500 grit (but this depends) then polish at 1K then depending on how well the Victorinox is looked after I will finish on 3K if it is an abused knife I will skip the 1K & finish on 2K. 

The microlevel I convex blend it into the thinning bevel so the micro bevel is barely seen. Finishing with a couple of passes on a strop.
I stress this is how I do it at the moment.

I find I rarely use course stones I will use them on the spine to repair tips or to blend bolsters (for instance found on Wüstofs)into the blade I see absolutely no point in a thick bulb at the end of the blade.

Carbon steels I will shape flatten initially with synthetic then progress to naturals.


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## ian (Jan 30, 2022)

@crockerculinary, how would you sharpen a Vic?


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## RDalman (Jan 30, 2022)

I would beltgrinder sharpen it against the wheel, with rotation and somewhere 10-15 deg/side probably (freehand). Just raising a burr with 60, then a100 gator making sure the burr gets flipped, and then deburr on felt wheel on buffer with white polishing wax. End result is thin and light convex edge. Impresses most folks and takes 10-15 min no matter what state the edge was in.


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## Leo Barr (Jan 30, 2022)

RDalman said:


> I would beltgrinder sharpen it against the wheel, with rotation and somewhere 10-15 deg/side probably (freehand). Just raising a burr with 60, then a100 gator making sure the burr gets flipped, and then deburr on felt wheel on buffer with white polishing wax. End result is thin and light convex edge. Impresses most folks and takes 10-15 min no matter what state the edge was in.


I would say in general it takes pretty much the same amount of time to sharpen a Victoriniox without any issues chips or tips or geometry by hand on whetstones as you mention using power tools plus I can do this in a restaurant kitchen.


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## crockerculinary (Jan 30, 2022)

ian said:


> @crockerculinary, how would you sharpen a Vic?


Well that’s kind of the thing, I’ve been jumping around so many different methods over the past couple months experimenting and trying to lock down a system for myself. Im about to start offering a tiered sharpening service with my basic sharpening done with belts, and then a premium stone sharpening where I can tailor things more specifically for the knife and user and charge a little more.

But to answeR the question directly I think the results I have been most happy with on belts (still using variable speed 1x30s, and honestly not sure I need anything more for sharpening, but will probably upgrade to 2x72 at some point for added functionality) has been a 3 step- starting with a 120 ceramic belt (Norton blaze) and a wet knife, first cutting in a relief bevel at about 12-15 degrees and then the edge bevel at 20ish until I get an even burr, then moving to a 600 grit silicon carbide belt and repeating that process while lightly convexing out the transition and scratch pattern on the slack, lightening the pressure to almost nothing to minimize the burr, and then finishing on a leather belt loaded with green compound. Usually do a light draw or two through wood for any remnants, although it’s usually clean by then. With the right (and fresh) abrasives I can usually do this with just 2 or 3 passes on the first two steps unless the knife is crazy dull and then usually a few extra passes on the stropping belt. The edge is usually super sharp but still has a good bite to it. I generally do most of my days sharpening in a single batch so it’s pretty efficient time wise.

On stones ive been playing around a lot with different coarse stones to set the same initial bevel angles but generally still stick with my chosera progression of 400-800-and finishing at 3k. For some reason I tend to prefer the naniwa SS 3k over the chosera most days.

One of the most frustrating things as a sharpener is not having the time to do direct testing of the durability of the edges myself, but I have been pretty pleased seeing and hearing back from the same customers that the edges are holding up. I generally try to push ceramic rods (and teach them good technique) on my customers for maintenance in between sharpening.

I feel the belt progression is a good compromise of stable, sharp, toothy, and maintainable, and fast to execute on my part. I still tend to favor, for knives like this, a 20 degree edge for stability, but definitely try to keep the behind the edge thickness in check for better cutting performance.

On the stones I wonder, for the victorinox, if the 3k is simply overkill, but I keep that part pretty minimal as far as the very edge is concerned and consider it mostly stropping for burr clean up and polishing up the bevel.


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## crockerculinary (Jan 30, 2022)

Leo Barr said:


> I would say in general it takes pretty much the same amount of time to sharpen a Victoriniox without any issues chips or tips or geometry by hand on whetstones as you mention using power tools plus I can do this in a restaurant kitchen.


definitely not time wise. I’ve timed myself a lot and it’s less than half the time generally for a full sharpening and WAY better on the coarse part of the process. The ability to just cut in a clean bevel on a super dull knife with just a couple of passes just can’t be done on the stones at the same pace. I wish it was true but it’s not. There are definitely advantages to all stones, like the portability you mention, but time isn’t one of them unless you’re Superman.


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## ian (Jan 30, 2022)

crockerculinary said:


> Well that’s kind of the thing, I’ve been jumping around so many different methods over the past couple months experimenting and trying to lock down a system for myself. Im about to start offering a tiered sharpening service with my basic sharpening done with belts, and then a premium stone sharpening where I can tailor things more specifically for the knife and user and charge a little more.
> 
> But to answeR the question directly I think the results I have been most happy with on belts (still using variable speed 1x30s, and honestly not sure I need anything more for sharpening, but will probably upgrade to 2x72 at some point for added functionality) has been a 3 step- starting with a 120 ceramic belt (Norton blaze) and a wet knife, first cutting in a relief bevel at about 12-15 degrees and then the edge bevel at 20ish until I get an even burr, then moving to a 600 grit silicon carbide belt and repeating that process while lightly convexing out the transition and scratch pattern on the slack, lightening the pressure to almost nothing to minimize the burr, and then finishing on a leather belt loaded with green compound. Usually do a light draw or two through wood for any remnants, although it’s usually clean by then. With the right (and fresh) abrasives I can usually do this with just 2 or 3 passes on the first two steps unless the knife is crazy dull and then usually a few extra passes on the stropping belt. The edge is usually super sharp but still has a good bite to it. I generally do most of my days sharpening in a single batch so it’s pretty efficient time wise.
> 
> ...



Nice. Sounds like a good progression. I often do just the coarse work on belts nowadays. This is mostly because so far I haven’t been able to get the same quality of final edge on a belt, but I also hardly ever practice at it. I also started getting a little worried about it recently when I heard Vadim (don’t remember last name) talking in his deburring book about a loss of hardness at the very edge when using belts and such. He says it can happen even in a way that’s imperceptible to the sharpener, e.g. the blade doesn’t get hot and there’s no discoloration or anything, but the very apex can get overtempered, leading to a loss of edge retention. Idk how much stock to put in this exactly, and I don’t remember how much it affects retention. But even with that, it still makes good sense to belt sharpen if you’re making a living off of it. That’s a good idea to have a special price for stone sharpening.

Durability is such a frustrating this to think about too…. I often wonder if I’m being too conservative with my angles because I’m afraid of the havoc the users with wreak. But the times I regret most are when I’ve been brash with my angles, setting them to what I’d use, and then the user comes back with a chip.


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## HumbleHomeCook (Jan 30, 2022)

Discussions like this always remind of the cheap kitchen knife sharpening video made by the living legend Stan Wilson.

If you're unfamiliar with Mr. Wilson's work, he's primarily known for pocket knives but he is as much an artist as a mechanical genius as master knife maker. His "no screw" knives and non-flipper flippers are marvels. Anyway, I digress.

Is he an edge master? Well, I don't know, but he's an edge pragmatist.


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## crockerculinary (Jan 30, 2022)

@ian Yeah, I was trying a lot of setting the initial bevel with the coarse belt and then jumping to the stones. I was very happy with that results wise, and I think that manages the overheating edge concerns, which I have as well. Time wise it wasn’t a big advantage switching methods. I try to manage that by working wet and relatively slow and precise. I’m pretty convinced it isn’t a big issue with how I do it- light pressure, working wet, never staying on the belts too long, but I am completely open to being wrong and adapting. Working at volume for low prices seems like there will always be a bit of compromise somewhere. Ultimately I think I might get a rotary whetstone as that seems like a good compromise. I really want to do some testing when I can find the time on the results and see how much it comes into play. Honestly not sure how to test for it other than just using them side by side for weeks on end. HRC tester maybe?
Anyway, getting off track as usual, lol.


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## Troopah_Knives (Jan 30, 2022)

ian said:


> The blade doesn’t get hot and there’s no discoloration or anything, but the very apex can get overtempered, leading to a loss of edge retention. Idk how much stock to put in this exactly, and I don’t remember how much it affects retention.



This is absolutely a real phenomenon. @Larrin and Roman did microhardness testing on blades that had been sharpened on a belt grinder and found significant drops in hardness. It actually could be a double whammy of bad because it seems the temperature can get high enough that you get into the martensite embrittlement. So your edge is getting less hard and less ductile. As to how much it affects edge retention I cannot say. I would guess however as long as you go slow and use water and do a fair bit of work on the stones to remove the heated steel it should be okay. At the end of the day if you are sharpening a cheap knife I'm not sure how much it matters. Some things dull fast no matter what you do.


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## crockerculinary (Jan 30, 2022)

Troopah_Knives said:


> This is absolutely a real phenomenon…


Oh yes for sure I know it’s real. I am very curious though about how the specifics of technique affects this. Things like how many grits, how many passes, how high in grit did they go, what kind of pressure was used, time spent on the belt, speed of belt, was there any water cooling at all or time taken between passes, etc, etc.

For example, Workaharps instructional videos spend a good bit of time on the belt and tell you for example to move slowly across the belts (I think they say an inch a second or something) and it’s just pass, pass, pass, pass, pretty quickly, So could different technique affect that?

I would love to see all how all those little details come into play, and if it’s possible to have no negative effects, or if it’s simply a matter all powered abrasives are going to be destructive period. I imagine the answer is yes, but is it possible to minimize that destructiveness to an acceptable level or not?

I do have a couple knives I use that I have sharpened this way for personal testing and I haven’t been able to notice a major difference in the day to day but it’s not exactly scientific evidence and Im always happy to be proven wrong.

Anyhooo,


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## crockerculinary (Jan 30, 2022)

double post


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## Troopah_Knives (Jan 30, 2022)

@crockerculinary I certainly have no idea on all the technique stuff. It must make a difference right? I know that wet grinding primary bevels combats the effect but I don't know if that follows for secondary bevels. It would be super interesting to know more!


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## ian (Jan 30, 2022)

Seems Larrin wrote this on the subject:









Does Sharpening with a Grinder Ruin Your Edge? - Knife Steel Nerds


You have to sharpen a new knife a few times to get it cutting well. Right? Or do you? Are knife manufacturers improperly sharpening their knives?




knifesteelnerds.com





I seem to remember that the Knife Deburring book went a little further and indicated some threshold belt speeds before which there was no discernible overtempering or whatever, but I’m sure there are a ton of variables there too. Like @crockerculinary, I’d be curious to know if it’s really a significant factor when I put a knife on the belt, given that I’m running a 2x72 on lower speeds, moving the knife quickly, and dipping it into a bucket on every pass. Drops in edge retention after sharpening dry on a 1x30 fixed speed Harbor Freight machine are interesting, but don’t necessarily apply.


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## BoSharpens (Jan 31, 2022)

Troopah, I can't thank you enough, really, for your comment on belt sanded hardness reduction on blade edges.

I spent my whole professional life designing medical plastic products and then making the molds. Never, ever in my whole life did I see a belt sander in a tool shop. You saw it in fab shops working on mild steel and such, but never on anything that had to stay hard.

I try to indicate to my customers and potential customers that I've seen over a half dozen common problems with belt sanded edges at the "Farmer's Market" including soft edges, but few people seem to really understand. I suspect some people think I am just trying to earn more money. I get it as they've never worked with steel & blades.

I'm still trying to figure a great way to explain the issues better to knife owners.


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## BoSharpens (Jan 31, 2022)

On an experimental level, I recall I did one time try to "rough" a chamfer on a blade for a fixture to cut heating wire. 

I put my index finger on the back side of the blade as I used a belt sander or grinding wheel to put the basic angle on.

With fairly lite pressure on the blade, it took less than a second or two max to start to burn my finger. That was about .06" from the other side of the blade. Hence, I would assume the metal in contact with the wheel was hot enough to get softened.

All the grinding we did on the surface grinder HAD to have high flow cutting fluid on it non-stop. If you did not do that, you got burn marks everywhere.


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## ian (Jan 31, 2022)

BoSharpens said:


> On an experimental level, I recall I did one time try to "rough" a chamfer on a blade for a fixture to cut heating wire.
> 
> I put my index finger on the back side of the blade as I used a belt sander or grinding wheel to put the basic angle on.
> 
> ...



This isn't really evidence against belt sanders, though. The fact that you at some point overheated an edge on a belt doesn't mean that others are always doing it.

When I do an edge on the belt, it's always cold to my fingers and there are never burn marks, since the blade is coated with water and the speed is low. The discussion above suggests that the precautions I take *might not* be sufficient to avoid overheating the very apex. But they don't say that the apex is definitely overheated. The only thing that you can say with certainty is that _some people*_ overheat knives with belts, which is obviously true.

That said, the discussion above makes me want to be extra-cautious with heat generation.


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## BoSharpens (Jan 31, 2022)

ian said:


> This isn't really evidence against belt sanders, though. The fact that you at some point overheated an edge on a belt doesn't mean that others are always doing it.
> 
> When I do an edge on the belt, it's always cold to my fingers and there are never burn marks, since the blade is coated with water and the speed is low. The discussion above suggests that the precautions I take *might not* be sufficient to avoid overheating the very apex. But they don't say that the apex is definitely overheated. The only thing that you can say with certainty is that _some people*_ overheat knives with belts, which is obviously true.
> 
> That said, the discussion above makes me want to be extra-cautious with heat generation.


Another user above noted using a belt sander set up to run lower speeds. That is likely what it takes to have controled blade work.

El-cheapo belt sanders don't have speed adjustments, however.

When people bring me knives to sharpen which have been belt sanded carelessly, I see lots of uneven edge angles & wavy edge profiles with occassional scratches on the side of the blade. It is just FAST careless work.


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## ian (Jan 31, 2022)

BoSharpens said:


> When people bring me knives to sharpen which have been belt sanded carelessly, I see lots of uneven edge angles & wavy edge profiles with occassional scratches on the side of the blade. It is just FAST careless work.



Absolutely. Before I got into all of this I had my knives sharpened a couple times by someone with a belt in a truck. They never came back much sharper than before (I didn't really know what to expect) and the bevels were crazy bad.


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## captaincaed (Feb 1, 2022)

I think I just figured out why they put Co in VG-10. They _expect_ people to give it to a grinder to sharpen it, and they want it to hold hot-hardness a bit better. Maybe?


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## Troopah_Knives (Feb 1, 2022)

captaincaed said:


> I think I just figured out why they put Co in VG-10. They _expect_ people to give it to a grinder to sharpen it, and they want it to hold hot-hardness a bit better. Maybe?



I hadn't thought of that. It would certainly help! Although I think the original reason was for putting different coatings on it which often happens in the 500f range.


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## M1k3 (Feb 1, 2022)

captaincaed said:


> I think I just figured out why they put Co in VG-10. They _expect_ people to give it to a grinder to sharpen it, and they want it to hold hot-hardness a bit better. Maybe?


@ian


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## ian (Feb 1, 2022)

Heard! Will now sharpen all VG-10 on worn-out dry belts at full speed.


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## M1k3 (Feb 1, 2022)

ian said:


> Heard! Will now sharpen all VG-10 on worn-out dry *high grit* belts at full speed.


Fixed it for you.


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## ian (Feb 1, 2022)

That goes without saying. VG-10 is crap without a 12k finish. Then it starts to shine!


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## captaincaed (Feb 1, 2022)

Troopah_Knives said:


> I hadn't thought of that. It would certainly help! Although I think the original reason was for putting different coatings on it which often happens in the 500f range.


Aaaaaahh that would fit.


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## captaincaed (Feb 1, 2022)

ian said:


> Heard! Will now sharpen all VG-10 on worn-out dry belts at full speed.


110% on the VFD! 88 miles per hour!


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## RDalman (Feb 1, 2022)

captaincaed said:


> 110% on the VFD! 88 miles per hour!


90 hz


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## ian (Feb 1, 2022)

That kind of speed is so unthinkable, it hurtz.

Edit: Bad pun aside, I just realized I have no idea what 90 hz means. So this is like 5400 rpm.... which I guess is kinda fast? But idk. I'm not smart enough to know what rpm I'm working with. I just set things to slow or medium or fast. Maybe I should work this out at some point.


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## M1k3 (Feb 1, 2022)




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## TB_London (Feb 1, 2022)

Depends on use - how has the edge failed - if rolled and chipped it needs the bevel thickening, if just blunted then can drop the angle a bit more. Arbitrary angles assume arbitrary use.

I’m gentle on my knives, so they’re thin behind the edge and cut with little resistance. I gave a knife like that to someone else who’s rougher on their knives and it was soon chipped and rolled. Thickened the edge up for them and was fine. We both know how to use a knife and use it our way- with the right bevel we’re both happy. I feel I lose performance with a thicker edge for no gain, they need a thicker edge for it to survive


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## M1k3 (Feb 5, 2022)




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## Troopah_Knives (Feb 5, 2022)

Very nice spreadsheet! The study done with the color-changing lacquer was very interesting and the spreadsheet is a great collection of data. 

The author made two key errors.

1. In regards to VG-10 and general interpretation of any steel that a manufacturer says "displays secondary hardening". Although it can be coated at up to 450c kitchen knives simply aren't tempered in that range and this could easily cause a loss in hardness of 6rc points so I would not recommend using a belt grinder to sharpen it unless you can keep temperatures below whatever the factories temper is.a

2. Many steels were not developed for knives and heat treatment can diverge significantly from the recommendations of a manufacturer. For example, it should be noted that many knife makers don't temper in the range recommended by the manufacturer as a better balance of hardness and toughness is usually achieved through a cryo treatment and low-temperature temper. So I still would not recommend sharpening steels like k390 on a belt as many makers use a 350-400f temper unless you know the tempering temperature used on the knife.

Basically to best apply the data in the color-changing lacquer study, unless you know the tempering temperature of the knife you are sharpening assume that any temp over 300f will soften your edge.

Finally as noted by the person who wrote the post highlighted "there might be a problem in the tests performed and that the very edge might have too little mass to transfer enough heat into the lacquer to make it translucent". So we still, unfortunately, cannot rule out significantly higher temperatures at the very edge of the knife. In fact, we can infer that in the original testing done by knifesteelnerds a higher temperature was achieved because the very edge of the blade actually showed an increase in hardness which could have been caused by secondary hardening (~1000f) or actual hardening of the edge (1400f+). With more extensive testing maybe we can get a better idea of under what circumstances that extreme heating occurs.


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## Dominick Maone (Feb 5, 2022)

I think the belt grinder ruins edge argument is strange. Seems like everyone believes whole heartedly that each steel can be heat treated 1000 different ways for 1000 different results. But using a belt sander ruins your edge in all circumstances. My belt sander can go so slow that I could probably have a knife on it for 3 minutes without burning the edge. Or so fast that it can turn a 1.5”x3 foot (38mm x 1m) bar of steel into dust in one minute.


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## Troopah_Knives (Feb 5, 2022)

@Dominick Maone are you talking sharpening or just beveling?


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## Dominick Maone (Feb 5, 2022)

Troopah_Knives said:


> @Dominick Maone are you talking sharpening or just beveling?


Was talking about sharpening specifically. But either really.


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## Troopah_Knives (Feb 5, 2022)

@Dominick Maone Im sure it is possible not to overheat your edge on a belt grinder it's more a question of how hard it is not to. It's rather hard to empirically test if you have overheated your edge as you need expensive equipment. With the short time scales, we are talking about the edge won't change colors. I have yet to see a single empirically study where a knife was sharpened on a belt grinder and didn't show any negative effects but once again I'm sure if you go slow enough it's possible. The real question is how slow, how much coolant, and what abrasives. Without more study, we won't know for sure!


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## crockerculinary (Feb 6, 2022)

Troopah_Knives said:


> Basically to best apply the data in the color-changing lacquer study, unless you know the tempering temperature of the knife you are sharpening assume that any temp over 300f will soften your edge.



this is all amazing and I’m so glad to see people are trying to get real data on this, but I am ADDaf and not very metallurgically edumacated AND charts and data make my head swim. So is this a good general takeaway? As long as we don’t hit 300f degrees, no damage will occur to the steels hardness?


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## Troopah_Knives (Feb 6, 2022)

@crockerculinary I'd say it say it's not a super helpful conclusion as that is exactly what we knew before looking that that big spreadsheet. We do know from the study linked in that Reddit post that it is easy to heat the blade above that temperature on a macro scale (no way to know how much worse if at all, it is at the very apex). In many cases, the edges were heated above 325(the min temp they looked at). On their belt grinder examples, they found 1-2 seconds of light pressure depending on the knife did overheat the edge. 

Basically, due to issues with measuring the heating at the very apex, the above studies don't tell us much other than 1-2 seconds of light pressure on 220grit belts will overheat your edge. We still don't know the important info of how little time do you have to do to not risk overheating the edge, and if constant water cooling can eliminate that.


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## ian (Feb 6, 2022)

Yea, still nothing conclusive or strongly suggestive that obviously applies to the way belts are usually used. Cool that people are trying tho.

I think the microhardness measurements that Larrin cited are still the most compelling data, but they also leave a lot of questions open.

The takeaway is still just “Be cautious about heat generation. It can be a problem even if the blade doesn’t get hot to the touch.”


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## Luftmensch (Feb 6, 2022)

ian said:


> That kind of speed is so unthinkable, it hurtz.





I am glad somebody is making these comments periodically!




ian said:


> Edit: Bad pun aside, I just realized I have no idea what 90 hz means. So this is like 5400 rpm.... which I guess is kinda fast? But idk. I'm not smart enough to know what rpm I'm working with. I just set things to slow or medium or fast. Maybe I should work this out at some point.



Your belt speed is almost certainly controlled by a VFD... a variable-frequency drive. This device converts your mains AC signal into a DC signal and then back into an output AC signal. The speed knob on your controller changes the frequency of the output AC signal connected to your drive motor. Basically Hz = RPM. By twisting the knob to 11 you get more speed.

Sweden has a grid frequency of 50Hz


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## HumbleHomeCook (Feb 6, 2022)

Somewhat related to the thread recency:


I say this because of something in the comments of the vid:
_
*philipp594*
11 hours ago
Why do you not rough grind it first, when annealed, then harden it and do the last little bit? Would it shatter during hardening? Or bend?

REPLY



Big Brown Bear
11 hours ago
How about I ask you, do you think that having areas of thicker and thinner on the blade would change how the same time and temperature are affecting the different sized areas during austenitizing and cooling? Also do you think there would be concerns about decarburization and warping? There must be a good reason why I am willing to spend more time and money to grind from full thickness eh?_

****

So Shawn does all his grinding post-HT. I believe he sets his edge bevel on the belt as well and then finishes by hand so it might not be fair info to toss into the mix. It just popped up in my feed and reminded me of this discussion.


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## ian (Feb 6, 2022)

Luftmensch said:


> Your belt speed is almost certainly controlled by a VFD... a variable-frequency drive. This device converts your mains AC signal into a DC signal and then back into an output AC signal. The speed knob on your controller changes the frequency of the output AC signal connected to your drive motor. Basically Hz = RPM. By twisting the knob to 11 you get more speed.
> 
> Sweden has a grid frequency of 50Hz



This is a funny post.  I'll get around to figuring out what RPM "100" corresponds to on my grinder one of these days.

In related news, I actually used my grinder at 60% speed for the first time today! Maybe in 5 years I'll actually use it on full.


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## crockerculinary (Feb 6, 2022)

To me that is a super useful takeaway. 300f is hot. I know what touching something 300f feels like. 300 burns fingers. So, let’s say I could have an infared thermometer pointing at the contact point of the knife/ belt, if I never hit 300, I wouldn’t have any issues?
(They way I use the belt I can’t think of a time where any point on the knife was on the belt for more than a second. And if it starts to get warm at all it gets pulled and dipped.)


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## Troopah_Knives (Feb 6, 2022)

crockerculinary said:


> To me that is a super useful takeaway. 300f is hot. I know what touching something 300f feels like. 300 burns fingers. So, let’s say I could have an infared thermometer pointing at the contact point of the knife/ belt, if I never hit 300, I wouldn’t have any issues?
> (They way I use the belt I can’t think of a time where any point on the knife was on the belt for more than a second. )



It's a bit more complicated than that. It's a game of thermal mass. The edge is very small and so heats and cools very quickly so dumping a small amount of heat (grinding) into the edge can raise the temperature significantly however it's not enough heat for you to feel or get injured. For an example of this phenomenon think grinding sparks which are easily 2000f+ cant burn you because they are so small they can't transfer enough heat to your skin. So just because an edge feels cool doesn't mean that it didn't reach a high enough temperature to over temper.

On the topic of infrared thermometers. Sure that would work in theory if you got one that read the temperature of a small enough area. Usually, they read about a 0.5"diameter area but you would need one small enough that it would read just the apex of the knife. 

Finally, It sounds like your current sharpening method would pass the test of the study that was done above. However, that study doesn't control well for thermal mass. Adding the lacquer to the edge basically acts as a heat sink for the very apex of the blade meaning the grinder needs to heat up much more material in order for the same temp to be reached at the edge. Basically, I would interpret their results as a best-case scenario. 1-2s will definitely overheat your edge. Less than that? Maybe maybe not. I hope that clears it up.


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## ian (Feb 6, 2022)

crockerculinary said:


> To me that is a super useful takeaway. 300f is hot. I know what touching something 300f feels like. 300 burns fingers. So, let’s say I could have an infared thermometer pointing at the contact point of the knife/ belt, if I never hit 300, I wouldn’t have any issues?
> (They way I use the belt I can’t think of a time where any point on the knife was on the belt for more than a second. And if it starts to get warm at all it gets pulled and dipped.)



I don't think that's the takeaway. The IR thermometer won't be able to measure temp right at the apex. The point is that there's no way you'll really know if the apex gets superheated, so you should be over-cautious if you're finishing your sharpening on a belt. It might be fine if you're just making sure that the blade doesn't get too hot to the touch, but it also might not be fine, so err on the side of over-cooling, at least if you're prioritizing good edge retention over time required to complete the job.


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## crockerculinary (Feb 6, 2022)

Got it, got it. I sure wish there was some way to know for sure if better technique on belts was able to avoid this. Is there any not ridiculous way to test this? I would really like to have a practical answer for whether or not the way I am using belts is able to avoid damaging the steel.

So are we convinced that water cooling methoda on belts controls this?


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## M1k3 (Feb 6, 2022)

HumbleHomeCook said:


> Somewhat related to the thread recency:
> 
> 
> I say this because of something in the comments of the vid:
> ...



He also grinds wet. He uses a water spray system to cool the blade down.


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## HumbleHomeCook (Feb 6, 2022)

M1k3 said:


> He also grinds wet. He uses a water spray system to cool the blade down.



Very good point!


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## Troopah_Knives (Feb 6, 2022)

crockerculinary said:


> Got it, got it. I sure wish there was some way to know for sure if better technique on belts was able to avoid this. Is there any not ridiculous way to test this? I would really like to have a practical answer for whether or not the way I am using belts is able to avoid damaging the steel.
> 
> So are we convinced that water cooling methoda on belts controls this?



There absolutely is. Using the methods that @Larrin used in his study and a much broader range of tests (different belts, speeds, cooling, etc) we could get a better idea of what's going on. Unfortunately, that would be a huge amount of work and the testing may be prohibitively expensive.

Water-wise: I'm sure it's not perfect but it should help a lot.


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## Bico Doce (Feb 6, 2022)

I personally cannot add any insight to the effects of belt sharpening on edge quality but I just came across this section on exactly that in Dr Vadim’s book - Knife Deburring.










edit: pg 53 - 54


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## Rangen (Feb 6, 2022)

The diversion to powered sharpening on this thread is very interesting. Not directly applicable to me -- I don't power sharpen, because I enjoy using hand tools, and don't enjoy using power tools, though of course I recognize their irreplaceable worth when needed.

The main question it raises in my mind is: will @ian now buy a Tormek? Or, even better, one of those massive grinding wheels you see in Japanese knifemaking videos, with a stream of water running over them all the time? If the latter, I want pictures.


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## ian (Feb 6, 2022)

Those water wheels are super cool. Props to sharpeners (like @JBroida?) that use them.


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## M1k3 (Feb 6, 2022)

ian said:


> Those water wheels are super cool. Props to sharpeners (like @JBroida?) that use them.


Quick fix! Garden hose and a spray nozzle!




Or do it the real way like BBB did...


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## ian (Feb 6, 2022)

M1k3 said:


> Or do it the real way like *BK* did...



Fixed. But yea, having one of those sprayers like BBB is my new goal.


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## Dominick Maone (Feb 6, 2022)

__





Kool Mist Misunderstanding?


I thought I had an epiphany the other day regarding wet grinding. Why can’t I just get a garden mister and use it with my hose? Getting a kool mist or a knock off is a little cumbersome because I will need to get a decent compressor also. So, I purchased the mister in the photos for 3.50...




www.bladeforums.com





BBB is using a kool mist system. Kamon is using flood coolant. Two different things. Check out my thread in another forum about a hose spray nozzle.


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## Luftmensch (Feb 7, 2022)

If it is a problem.... I wonder _how much_ edge (volume) is 'burnt'? Power grinding the primary bevel and finishing on whetstones seems sensible. It had better be... The practice is common enough. Do you have to spend 10 minutes on the whetstones removing the ruined temper.... or 30 minutes?

... obviously the answer depends. But let's say the edge was never uncomfortably hot to the touch.... Surely the amount of material that was cooked (if it cooked) will be tiny?


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## Brian Weekley (Feb 7, 2022)

Interesting subject. For those who are interested I found this video worth watching.



I’ve been a “home” sharpener for a long time and my techniques have evolved over time. As my eyesight has deteriorated I find myself sharpening by ear a lot of the time. Anyway here’s where I’m currently at. Victorinox and “German” steel knives get the Tormek. I may finish them with a few stripes on a 2k stone if they didn’t come to me abused and beat up, but that’s it. Artisan and Japanese knives get the stones, generally 400 grit (if they need a bit of thinning) to 6K … whatever is necessary. Currently I love using JKI’s 1k-6k vitrified Diamond stones, especially on harder steels. Edge angle depends somewhat on the steel and the condition the knife arrive in. I charge a lot more for sharpening on the stones. I don’t do folders, scissors or chisels. Is my way the best way … not that I would claim. I’ve bought quite a few knives. I’m amazed at the quality of the edges that have arrived on knives I’ve purchased from some KKF members. There are some members on KKF who are really capable of putting edges on blades … probably using stones.

I’ve never used a belt sharpener. I watched the previously mentioned video with Ryan Swanson and was “gobsmacked” at the facility with which he used his belt grinder. Free handing in a way the caused the hair to stand up on the back of my neck at times. Power sharpening is, in my opinion, dangerous for me. I have to pay a lot more attention and concentration using the Tormek than I do using stones, especially in edge leading mode. In the process of doing my time with TF’s I bought two knives from District Cutlery … a petty and a 195mm nakiri. I paid Ryan to “thin them as he thought necessary“. He did a pretty good job. They arrived scary sharp and nicely thinned … a more consistent job than I would probably do using stones. Has the edge of the blades been adversely affected? Only time will tell whether TF’s great edge life has been affected, but I don’t think so.

I’ll probably never use a belt sharpener. I don’t think I have the energy at this stage in my life to deal with the learning curve. I’m happy with the results I get from my stones. I would, however, be uncomfortable turning a quality blade to a sharpener who uses a belt sharpener. Skills differ and it seems to me that the primary reason for a sharpener to use them (apart from putting an initial edge on a new knife) is speed … sharpening more knives at less cost For more revenue. That’s not my thing and I’m not depending on income from sharpening for my daily bread.


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## Bico Doce (Feb 7, 2022)

Brian Weekley said:


> Victorinox and “German” steel knives get the Tormek.


A Tormek looks like a lot of fun to use. Just out of curiosity, how do you maintain the angle on the Tormek as you approach the tip of the knife assuming there is a belly/upsweep to the blade?


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## Brian Weekley (Feb 7, 2022)

Bico Doce said:


> A Tormek looks like a lot of fun to use. Just out of curiosity, how do you maintain the angle on the Tormek as you approach the tip of the knife assuming there is a belly/upsweep to the blade?



I keep the Tormek set at about 22 degrees. This seems like a good setting for the types of blades I sharpen using it. I raise the blade away from the stone as I reach the curve towards the tip … just as I would using a flat stone. In this way I maintain a more or less constant sharpening angle blade to stone.


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