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So far, since I've started business officially this year (February), I've sharpened about 90 knives (with 3-4 repeat orders)

Only 4 knives did not have any damage
- 1 Katto santoku
- 1 Shun Santoku
- 1 Richardson Sheffield cleaver
- 1 generic cleaver (Hakkoh brand)

Common damage encountered, from most frequent to least:
- Concave blade profile
- Broken knife tips
- Chips extending beyond secondary bevel
- Severe corrosion
- Blade bent away from knife handle (out of alignment)
- Warping of blade above chipped area
- Knife tip bent to one side
- Lateral cracks on blade (parallel to spine)

So as a rough estimate, approx. 80% of knives handed to me have one or more types of damage listed.

I suspect it can be quite the cultural thing as well. Where I'm at (Singapore), disposability is the name of the game, and choosing repair over replacement is still considered a "new fad". Knife sharpening and repair is still considered menial dirty blue collar work, and people still think in 1980s prices.

My question for those of us with higher sharpening volumes than me is, How many of the knives you sharpen are "very dull or damaged"?

I think a good place to start would be to indicate the volume of knives you sharpen, to get responses from your target demographic.

When I started my sharpening business, I would tell customers my sharpening plan, how I created it, and what I planned to achieve (approx. 200 BESS and lower, sharper than brand new)

The one thing I never anticipated was how almost all customers would gauge quality and sharpness through appearance, and nothing about how the geometry was created to match their usage. So the underlying question of my initial post was to get an idea what "standards" other people in this forum work towards.

I've had a recent customer complained that I had scratched up his knife. But when he was shown the initial photo he sent to me, he then realised I had actually removed majority of scratches, and lightened the deeper ones. His only feedback about a deba knife I had sharpened for him earlier? "My wife cut her finger" 🤔🤷🏻�♂️

Customer behaviour still remains a mystery for me.

Consider a hanging leather strop as a user friendly alternative.

It's flexible, conforms to the cutting edge (especially useful for people who sharpen infrequently), and it won't change the blade geometry so much that you'll have to reprofile their knives each time they bring them over to you (saving time)

The risky part of providing an alternative (like a honing steel) is that you're not there to stop bad technique, or over sharpening.

Even though I sharpen knives for a living, I don't sell customers any sharpening tools, only a leather strop mounted on a rectangular plastic backing. That way, it's much more forgiving to bad technique, and saves me time with reprofiling the next time they visit. (I've repaired too many concave knives to trust customers)

This may be a good place to start

https://slipakniven.com/product/adapter-for-2-wheels-long-version/

I've used my DC-250 since... December last year? It still cuts very well for 360G, but for faster reprofiling, I still use my SG-250 (graded to 220G)

Every 1-2 weeks I clean all my diamond grindstones in my ultrasonic cleaner, then "rinse" them in the ACC-150 solution by mounting it on my T8, then running it through the water trough for a few minutes.

I would recommend getting a combination of SG-250, DC-250, and DF-250. These should cover almost all knives (and scissors) you can throw at it. I chose to use mainly diamond grindstones because I wanted to speed up grit progression by using the same diameter grindstones (and also to sharpen ceramic knives)

Most knives I sharpen with the DF-250 (600G), I barely see the scratch pattern after honing on the LA-220 leather wheel. If you're pursuing a mirror-like finish, then the DE-250 (1200G) would be an economical and practical choice.

I do use my DE-250 (1200G) and SJ-250 (4000G) for commercial chefs (and some customers) who request for it, but that's far and few in between.

I have all 3 diamond grindstones for my sharpening business.

I typically use the DC-250 (360G) to reshape/reprofile blades, and sharpen with the DF-250 (600G). Only when the customer wants a finer edge (and willing to pay more), do I use the DE-250 (1200G)

From personal experience... Going from the DC-250 to DE-250 is going to add a lot of time to your sharpening. Some factors to be considered are hardness of the steel, and what level of sharpness you're trying to achieve.

I spend most of the time at the DC-250, lesser time with the DF-250, and the least time with the DE-250.

So it's definitely a possibility, but the time take  is going to be hella long.

Many thanks for the follow up Nick.

I currently record images of customer knives, before & after, as well as digital microscope images of the before & after.

I don't typically send them out to customers post work, and use them more like a "break glass in case of emergency" type deal... You know, in case I get that unsatisfiable customer.

But I got a good review from the customer, so it all ended up well. But I'm always thinking of how to recreate good results more consistently and predictably in future.

Totally agree with you Nick.

I think a bit of background to this "theory", is that I'm still working on a framework to categorise my sharpening services pricing for my business, as well as streamlining workflows.

Almost all my customer knives have required repairs of different extents, and I was tired of doing these repairs without getting properly paid.

So I developed a framework (that included estimated bevel height) so that I could consistently move customers towards the appropriately priced service tier, to be fairly paid.

So when receiving knives, I measure the behind-edge-thickness, estimate the bevel width, and let them know what the final product will look like. Most of them gauge the quality of service based on the appearance of the knife (strange, I know) I still find it odd how my sharpening business really picked up after I got a bench polisher.

So, for this knife in conversation, I told the customer beforehand that the recommended sharpening angle range (15-20 DPS) would produce a bevel of 1mm width or less, and it would be hardly noticeable. And if she was agreeable with it, then I would proceed with work.

I actively try to avoid getting into disputes with uninformed customers who receive their knives post sharpening, and ask me why almost nothing was done, because they didn't notice any significant difference. (When handing over knives, I typically do a paper cut test in front of them, before they make payment. Using my PT50A test results just goes over their heads, but they can recognise a paper cut test)

So thinking back, my question was more of dealing with customers and what standard of work was deemed "acceptable", in a commercial sharpening context.

Many thanks for the responses.

I'm already done sharpening the chef knife, and the edge meets my standard of sharpness.

I think I was more curious about what kind of "standards" professional sharpeners work towards, especially when adding uninformed customers into the equation.

Regarding the bevel width, it's just my working theory that if the bevel width is too narrow, then the knife would have more difficulty slicing softer food (like meat) because before the bevel can start the cut, the primary bevel would be trying to wedge itself into the food. If the bevel width was too wide, then it becomes more vulnerable to rolling over/folding. So it's just based on observations from customer knives, my own knives, and brand new knives in stores, that I try to work towards a 1-2mm bevel width.

Good point, I asked about how to sharpen, but the focus of the question was not exactly aligned with what I asked.

Part one of question:
Seeking advice on how other Tormek users would sharpen a knife with an extremely thin blade (0.5mm behind edge thickness)

Part two of question:
Would a <1mm secondary bevel width be considered acceptable? (I typically aim for 1-2mm bevel width, in conjunction with the sharpening angle)

This knife is already sharpened at 15 DPS, but the secondary bevel is <1mm wide. So I'm just looking for advice if this is commonly done, or generally considered too narrow.

Just on a hunch, use a marker pen to mark the secondary bevel on your Japanese knife, and try a few light passes. See where the marker has worn off.

I typically sharpen Japanese knives at about 10-12 DPS.

My suspicion is that your sharpening angle of 15 DPS may be a bit too obtuse for the original edge.

A customer recently handed me a few knives for sharpening. Among the 5 knives (all Anolon brand), 3 of them have deep grind marks along the entire length (I'm going to guess it was from a bench grinder)

What I've done so far for the chef knife in question:
- Polished the entire blade to lighten scratches and to reduce the visible impact of previous grinding.

- Reprofiled the blade with the SG-250, and reduced the full bolster's width/length to match the blade heel. (The knife was banana shaped, with two knife bellies on the blade.)

- Sharpened with the DC-250 & DF-250 at 15DPS, honed with LA-220.

My question:
How would you sharpen a chef knife with a behind edge thickness of approx. 0.5mm? (No error, it's 0.5mm) I've tried and the secondary bevel is approx. 0.8-0.9mm. Would you consider a secondary bevel so narrow to be "complete" or "sharpened"?

Attached image is before sharpening.

[Me:]

My latest encounter with customer logic:

Me: Your knife tip is broken, do you want to repair that? There's an additional cost to grind down that section.
Customer: No no, there's no need. I don't use the knife tip.
Me: *thinks about knife constantly getting caught on cutting board* Okay

Me: Your cleaver has a lot of rust on it, do you want to remove it?... Or do you have any polish at home to remove it on your own?
Customer: Hmm... mmm... The rust is fine, no need for removal.
Me: *thinks about all the bacteria and food getting stuck in the blade, and rust flaking off onto food* Okay

Customer: I tried sharpening the cleaver on my own, but it couldn't pass the paper cut test.
Me: Yeah... It's a meat cleaver. It's got a very wide edge angle and made of softer steel because it's designed for breaking and splitting food apart, like a tiny axe. It won't really pass your "paper cut test" because the angle is really wide... What have you been using it for?
Customer: It was given to me brand new, unused. I haven't used it yet.
Me: *thinks about repairing yet another botched sharpening* Okay

Customer: After your sharpening, my knife looks very different, seems smaller!
Me: Yeah, knife sharpening works by carefully removing metal to create a sharp edge. All knives get smaller during sharpening, never bigger.
Customer: Ah yes, it makes sense.

Edge retention is still something that is somewhat of a mystery to me.  I have tried 600 grit and very little honing to highly polished.  Neither seem to be superior in terms of edge retention.  That is, retaining a 70 edge on the BESS.
After use, all steels I have sharpened lose that super sharpness in the first couple uses.  Some steels jump to a 140, some to 240 on everything but the softest foods.
They all seem to lose that eye popping sharpness very quickly.
I only have my tests to gauge this on.  I haven't seen any tests for real world usage to measure how fast the edge degrades.  I suppose CARTA tests do show the degradation but usually they demonstrate how long the usable edge lasts, not how long they stay ultra sharp.
Once again, how sharp you need/want to keep your tools/knife is very personal.  I had a carpenter look at a chisel sharpened to 90 like it was meh...

One thing I discovered during the course of my knife sharpening business, is how some customers reject modern sharpening methods (like my Tormek T8) to validate the methods that they've been using for the longest time as still "the best".

So the carpenter treating your 90 BESS sharpening as meh, may very well have nothing to do with your processes & results, but more to do with him trying to validate what he's always been doing as still "the best". A real life example, is how a local butcher turned down a free sharpening from me because he only believed in his own sharpening methods. His knife had only been thinned, no secondary bevel left, and the mystery whetstone he was using was like a misshaped bar of soap.

Another example was how a restaurant owner who was proud of learning how to sharpen knives since he was 14 (he was in his 50s when we spoke) but couldn't define what "high carbon steel" was, had no concept of knife geometry, as well as knife anatomy. The biggest indicator to me was when I offered to do a sharpness test on any of his knives for free (using my PT50A), and he immediately refused. That told me that he was rejecting me not because my methods and case studies sucked, but he was more worried that I would make his knives actually sharper, and totally invalidate everything he thought he knew.