thinning questions (yet another thread)

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Man stop with the measurements already. Really you've proven us, as you should have yourself, that your work is good. And what you seem to take out of it in general is that the knife performs overall marginally better.

Now is it impeccable... or the true question, is it just exactly how good you wanted it to become? Both are really just two different stances to a same goal... and a world of personal discinctions still.

It will take more than one knife before you'll just know. And that's ok. Notice a common point to all the best answers you've gotten already: these folks have much more experience than you.

I appreciate where further questioning comes from. No, I truly do: it's BECAUSE these folks have so much more experience than you. And so it happens, even there, that you as an invidual carry some doubts about even what these folks said. It is not because you consider yourself better, probably more quirks of your own singular experience at once with specific knives and thinning those specific ones in your best means - which of course, comes with many doubts.

Having doubts where you are is healthy. Having them even against experienced discourse is even better: it proves you sort of know what you want even though you can't entirely express it with the work nor the words. There's muscle memory in you that tells you: well this is not helping ME much, and that particular opinion goes against my grain, and then the brains come in and states: since it comes from an experienced folk, well I must be wrong.

But the truth of it is, so far and within how the back and forth happens, you both are wrong and/or right. They've got good background to tell you stuff. But since it's always gonna be you doing the next work, well you've got good background as well to hold onto some of your ideas, feelings, opinions, especially where these correlate instantly with your experience. And correlating with you experience is not only "science" you can theorize on indefinitely. It's muscle memory and the instinct and results thereof.

If you'd have presented really poor results, I'd push you towards listening to the folks. But where you've carried your work at already, it really will more come down to you. Like, being open to what folks say, but keep your doubts and stick to your experience. Do a few more knives - or try to make even better of the ones there in your possession. You'll know for yourself. Unlike me you can be patient about it and learn without compromising yourself. Or like me you buy lots of stuff for a couple years and don't hesitate a second throwing them all to the stones after some initial courtesy period - that is trying and understanding the tool before you, especially where it has some unexpected good attributes despite your so far common sense/general KKF view that it's "not very good".

What won't help you much I truly believe are these two things:

- measurements
- just blindly "do as said" and risk to lose the entire foundation you'll most readily learn from: what you've experienced and your own doubts and how you can school yourself from establishing a rationale between them and the most "instinctively helping" advice folks will give you along the way.

As you can see none of these forbids questions. But when you have like four-five questions, you're bound to encounter 4-5 different people that either worked with radically different knives than yours, either have 4-5 entirely cutting styles "agglomeration" of what's good according to them you'll never entirely tally with because it just doesn't work for you - by which I mean no obstination on your behalf, just not getting the cutting food results you figure the work should have garanteed with THAT knife that is in YOUR hand.

I've been there countless times. More often than not, in my errors of a learning curve mind you, I've found it to be a question of wanting to finish pretty and achieving it through some tricks or some real down to essential work: it'll either come as overpolishing or making something uneven very very flat. Both places are ESPECIALLY what I will do my damnedest to avoid beyond ANY other criterion you'll throw at me to question the work I do.

So according to my experience: you can thin a knife superbly and find it to be no real better than before: you've made the easiness of separation perfect, but food sticks 66% more than it did before, and suddenly the whole behavior of the knife, even where it essentially cuts excellently now, will not come out as effective as the initial no-effort cutting would like to prove it is. In most cases it traduces itself by alleviating or eliminating things like wedging or feeling blunt/low key in denser food, yet to the cost of worsening the sticking, suction, or natural food release of the knife. Which is sometimes said to be a non-variable, like cutting styles and geometry and blade type are much more important factors and such...

Well yeah they are, so you should... do... what: throw the blade to the trash? Sell it at lost? Never buy that type again? Seeking totally different geometry? Well... perhaps you should but let's start from a legitimate point where, if you decided to work on the knife, it was worth it to your eyes. What did you do that contradicted the improvement you're bound to have noticed as well, as a result of your best bet and careful work of making it better AND visibly without messing it up at all?

Do you really think I could give you a "Rule" into any of that? Otherwise than rather a "better not to" and "will work most of the time" general stance around which to attune the particular work a particular knife to your particular eye needs done. But then my advice wouldn't accord itself so well to your eye. Perhaps mine has seen more than yours... but then, just perhaps yours didn't need to see so much before doing it better than I can already.
 
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If you'd have presented really poor results, I'd push you towards listening to the folks. But where you've carried your work at already, it really will more come down to you. Like, being open to what folks say, but keep your doubts and stick to your experience.
If I may tangent a footnote: @ModRQC is encouraging “self-efficacy”
https://longevity.stanford.edu/self-efficacy-toward-a-unifying-theory-of-behavior-change/
https://serc.carleton.edu/NAGTWorkshops/affective/efficacy.html
I was just thinking about this while secondhand-watching instructional videos on parallel parking: so many mysterious heuristics and rote instructions, so little mental modeling and encouragement to practice and play to learn the more generally applicable skill of, well, driving in reverse!
 
I’ll modify your modification - which I think is a brilliant comparison - with the « logical » self efficiency that the OP is not showing anything like blades full of arbitrary stones scratches that did not do anything much towards thinning. On the contrary…

Thereof the logical complementary modifier in that sense: how would he really know that he did/didn’t get there at all? If he did how could I alleviate his still rigthteous doubts… if he didn’t how could I show he should do better than what seems like pretty good work for a guy with so many questions still to so limited experience?

Well… that he should go into it, take for cash value advice that sounds instinctively good, forget about the so-called maths of measuring BTE, and instead from practice go into logical BTE for a knife’s advantages and geometry while keeping in mind that the extent of such work shouldn’t jeopardize how he liked the knife as it was presented to him?

Ah yes… such exercise of self-proficiency… they usually yield shortly enough along the road that 4-5 questions about how, usually come down to one totally different question like for example in this instance: which best coarse stone? or Pratical level of polish? or First time with a wide bevel please help me get it right?
 
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Well, I have learned a lot from the thread.

I wrote my questions as my best attempt to understand what people are taking about with regards to "thinning". They were only posted after reading many threads, and watching videos. It is for me, less a matter of “self-efficacy”, than understanding what I am reading/hearing.

I don't think I have been overly focused on measurements, other than a recent post done because the measurements were requested. Yes, there were a lot at the beginning. That was a starting point that made sense to me at that time.
 
As the least experienced person on the thread it sounds to me like the knife is just idiosyncratic… with the reverse of distal taper maybe it just wants to do forward slicing push cuts or whatever, and not any other kind, and that’s just how it is!

@noj I don’t doubt you’ve done your homework and for sure a key aspect of learning is simply grounding the terminology to the right concrete associations.

That said this video may be relevant: Video for those that are interested in sharpening single bevels.
 
As the least experienced person on the thread it sounds to me like the knife is just idiosyncratic… with the reverse of distal taper maybe it just wants to do forward slicing push cuts or whatever, and not any other kind, and that’s just how it is!

@noj I don’t doubt you’ve done your homework and for sure a key aspect of learning is simply grounding the terminology to the right concrete associations.

That said this video may be relevant: Video for those that are interested in sharpening single bevels.
You know plenty;-)

Please ignore any implied annoyance with anyone, it was not intended.

Thanks for the link, will have a look.
 
As the least experienced person on the thread it sounds to me like the knife is just idiosyncratic… with the reverse of distal taper maybe it just wants to do forward slicing push cuts or whatever, and not any other kind, and that’s just how it is!

@noj I don’t doubt you’ve done your homework and for sure a key aspect of learning is simply grounding the terminology to the right concrete associations.

That said this video may be relevant: Video for those that are interested in sharpening single bevels.
Saw that video a while back, and said "Aha! That's what's going on";-)
 
I’ll modify your modification - which I think is a brilliant comparison - with the « logical » self efficiency that the OP is not showing anything like blades full of arbitrary stones scratches that did not do anything much towards thinning. On the contrary…

Thereof the logical complementary modifier in that sense: how would he really know that he did/didn’t get there at all? If he did how could I alleviate his still rigthteous doubts… if he didn’t how could I show he should do better than what seems like pretty good work for a guy with so many questions still to so limited experience?

Well… that he should go into it, take for cash value advice that sounds instinctively good, forget about the so-called maths of measuring BTE, and instead from practice go into logical BTE for a knife’s advantages and geometry while keeping in mind that the extent of such work shouldn’t jeopardize how he liked the knife as it was presented to him?

Ah yes… such exercise of self-proficiency… they usually yield shortly enough along the road that 4-5 questions about how, usually come down to one totally different question like for example in this instance: which best coarse stone? or Pratical level of polish? or First time with a wide bevel please help me get it right?
I find your comments un-helpful. I have a rather hard time parsing the English and/or meaning. Knife maintenance isn't my full-time occupation. I still spend plenty of time learning (reading, watching videos, and trying different approaches). If after that I still have questions, I would like to think this forum is a good place to ask. Everyone's approach to learning (and many things in life) will be somewhat different. I don't feel like I earned this level of criticism. I am not deterred in my interests, nor do I wish to argue my position, so I will leave it at that.
 
My apology to in advance ModRQC if I read it wrong. I just wanted to feel welcome to ask questions, especially if I did my homework first;-)
Ask as many questions as you please. That is what we are here for. Sometimes I get a little paranoid that ChatGPT is milking us for info. If you can't understand what that dude is talking about you are clearly human.
 
English is the second language, so I believe they get a bit careful with how they word things.
 
Not a criticism, I read it more as “dude is getting good results and should therefore be more confident that his mental model of what’s going on is indeed correct, my advice is not needed”.

If he’s reacting to anything it’s probably to years of watching beginners go by – not you – who seem to be looking for specific rote instructions to follow, when the more appropriate meta-method is simply the key learning loop “figure out what is real, in front of you; imagine a future that you want; hypothesize about how a particular intervention might work; apply abrasive accordingly; evaluate results; reflect and repeat.”

This is the lesson of the brick.

As the Zen master said, “when you become one with the OODA loop, there is no difference between archery, flower arranging, pottery, and knife sharpening.”
 
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I find your comments un-helpful. I have a rather hard time parsing the English and/or meaning. Knife maintenance isn't my full-time occupation. I still spend plenty of time learning (reading, watching videos, and trying different approaches). If after that I still have questions, I would like to think this forum is a good place to ask. Everyone's approach to learning (and many things in life) will be somewhat different. I don't feel like I earned this level of criticism. I am not deterred in my interests, nor do I wish to argue my position, so I will leave it at that.
My apology to in advance ModRQC if I read it wrong. I just wanted to feel welcome to ask questions, especially if I did my homework first;-)
You didn't need apologizing. And by the point of the message you quoted, I was more answering/philosophing about what @mengwong said, where the "subject" was a theoretical "beginner" with the right set of skills and the right vision. Which applies pretty well to you. I was surmising that with a bit more experience about it in you, your vision and questions would simplify dramatically.

I'm sorry if it looked like I was minimizing you, or going against your right to post as many questions as you want.

What I was saying all in all and all along is you did pretty good work, and I'd focus on that vibe by doing more. As much as you can.

Might need to buy a couple low-priced not so thin "project knives". It's really a good way to always have some work to do, and export your best "experiments" and developments to your better knives as you go.

It's healthy and fun, really, feeding one's addiction into buying new/different knives at the same time. :D

Ah yes and when you make these better, it really shows big time, and the feeling is great.
 
I have related questions, but wasn’t sure whether it’s proper etiquette to continue this thread on a (perhaps) related topic, or start another. If there is a thread already I should post to, let me know - I looked but it's not obvious.

Here’s a bit about my interest. It isn’t formulated as questions yet, but should give you an idea of where I am coming from. I have recently been learning about thinning and relief bevels. However, I have not been able to fully remove high (low) spots. I have experimented on a few knives, and have some observations and ideas. My focus is more on knife performance in the kitchen. At a minimum I want to avoid degrading performance from bad blade shape. If the blade looks nicer or performs better with this finish vs that finish, I imagine can adjust that as desired. Bottom line: I appreciate a better finish after working thinning and relief bevels, or a blade that is sitting unused for a while. I am also interested in knowing when not to work on the finish, or when to give up because of certain observations.

If this is a new topic, I am not sure what to call it. I have seen people using terms like "pre-polish", which makes sense to me. I have seen people use the term "flattening" in the same context (or so it seemed), but felt unclear with convex bevels and/or non-uniform distal taper, depending on what dimension is being flattened. Maybe there is or isn't different terminology.

Thanks!
 
I have related questions, but wasn’t sure whether it’s proper etiquette to continue this thread on a (perhaps) related topic, or start another. If there is a thread already I should post to, let me know - I looked but it's not obvious.

Here’s a bit about my interest. It isn’t formulated as questions yet, but should give you an idea of where I am coming from. I have recently been learning about thinning and relief bevels. However, I have not been able to fully remove high (low) spots. I have experimented on a few knives, and have some observations and ideas. My focus is more on knife performance in the kitchen. At a minimum I want to avoid degrading performance from bad blade shape. If the blade looks nicer or performs better with this finish vs that finish, I imagine can adjust that as desired. Bottom line: I appreciate a better finish after working thinning and relief bevels, or a blade that is sitting unused for a while. I am also interested in knowing when not to work on the finish, or when to give up because of certain observations.

If this is a new topic, I am not sure what to call it. I have seen people using terms like "pre-polish", which makes sense to me. I have seen people use the term "flattening" in the same context (or so it seemed), but felt unclear with convex bevels and/or non-uniform distal taper, depending on what dimension is being flattened. Maybe there is or isn't different terminology.

Thanks!
It’s a place where you need to find yourself. Answers cannot replace your own experience, especially where people will have varied opinions about these matters.

My experience at some point taught me a couple of things:

- I don’t concern myself with regular low spots but a muddier progression helps to camouflage them a bit better. What I don’t want to happen is to flatten the bevels. It doesn’t correlate well with food release.

- I’m particular about certain kinds of finish I want to keep as close to original because they’ve behaved well with food release as well.

Such decisions can impact the level of finish. While I don’t like thinning scratches or visible low spots no more than anyone else, I accept them in some cases of such minimalistic refinish to preserve the original as much as possible.

Have fun!
 
Before I get into specifics, and examples, I'd like to ask about terminology. It may help in terms of communication, as well as my search results.

Specifically, I am looking for the best terminology to describe the refinement of the bevel shape. I have seen "pre-polish", "flattening", and other terminology, but it's not very clear yet. The term "pre-polish" may apply, but I don't know if there's a meaning in this context (other than before actual polishing). Unless one has (or wants to create) a wide bevel, I am not sure why flattening makes sense.
 
I’m not sure there’s a terminology to describe what you consider in between there.

In all essence if you’re still removing steel you are thinning. But yeah inside a discussion people will tend to differentiate bulk thinning from what I myself would probably call fine tuning or refining. I just don’t think there’s a specific terminology that’s widely used enough to be considered as official.

I like you sure don’t like the terminology « flattening » unless that’s specifically your aim.
 
I call it “working on the knife’s geometry (on stones)”.

Flattening means making a flat bevel.

Prepolish means using lower grit stones to shape the knife to a point where you can use higher grit stones to polish it, and is therefore slightly more specific, although some people might think it’s the same thing.
 
Yet at any point where you either work a geometry, flatten or prepolish, you’re still thinning in essence. When you are not thinning is when geometry and anything in between stays the same. Otherwise the only way it’ll go is thinner.

Essentially.
 
To me, ‘thinning’ is more specific, and means that currently the knife is too thick behind the edge, and you’re trying to change that. I wouldn’t call removing low spots thinning, even if the knife is on average getting thinner.
 
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Its not all black and white. There is a lot of grey in this terminology.

For example: to remove low spots, you need to thin the bevel. You do that by grinding, or polishing. But in Dutch, polishing is more used for making mirror shine. By grinding the side, you change the geometry. etc etc
Pre polishing is everything up to the last gritt.

It's all about context i guess.
 
If you are not working on the edge/apex its a form of thinning for me. Then you can be more specific in terms of what the end goal is. Like flattening a bevel is a form of thinning with specific goal is mind.
 
I can say more about my individual projects later. Each one had it's own characteristics. Several projects were done before I knew much.

Knives I worked on:

1. 40 year old nakiri (thin, inexpensive)
2. 40+ year old Sabatier chef's and petty knives
3. H. Togashi Nakiri (discussed in this thread)
4. mukimono (in a different thread)
5. Forgecraft chef's knife (discussed in this thread)

In general, I was either fixing a defect (frown, low spot at the edge, etc.), general "thinning"*, or making a "relief bevel"*. Let's call these (kitchen) "performance enhancements" for now. I usually did some form of "pre-polishing"**.

Here are some of the problems I ran into after making the performance enhancements. These are not written so as to be unrelated.

A. Learning when to stop. Some knives are not made with a geometry that can/should be ground uniformly, other than near the edge. A simple example was my Sabatier chef's knife with a low spot that is bigger as you approach the spine.

B. Removing convexity when not intended. I find this happening when thinning (or pre-polishing with course stones) and working on low spots. I think some of this happened because I used too fine a stone, and got sloppy/lazy after 20+ hours.

C. Having a hard time removing hard steel at the same rate as soft steel. Maybe related to (B) above. I am using finger pressure as best I can. Sometimes I try raising the spine, but I am not sure that’s always desirable, and hard to get right.

D. In pre-polish, I often see what looks like a subtle low spot of the soft steel just above the hard steel, and can't seem to remove it. Maybe related to (B,C) above. Can grit get stuck there, thus grinding a low spot while trying to remove it?

E. Bent mono-steel. My Forgecraft has a little bend. After putting it in a jig and putting enough body weight into it, I decided it was unsafe for both me and the knife. I'll probably just live with it as-is.

F. Ideas for next steps in learning? Most of the 5 mentioned have little convexity. I don't want to experiment further on the Sabatier or single bevel.

Thanks!
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* Per discussion in this thread, a "relief bevel" was removing limited thickness behind the edge. I forget if there more specifics, but I had the notion the work was mostly done within 5 mm or so of the edge. More than that gets scratched if you want to blend things smoothly. General thinning is more than that. At least, I am going with this idea for now.

** Per discussion in this thread, "pre-polish" means using lower grit stones to shape the knife to a point where you can use higher grit stones to polish it. I imagine that includes modification of geometry that (mostly) isn't for performance: removing low spots away from the edge, blending bevel angles, etc. Obviously, the final finish affects performance, but no need to get into that for the definition.
 
Can grit get stuck there, thus grinding a low spot while trying to remove it?

Well, if you are trying to correct subtle low spots, it’s good to have a flat stone with no mud. I’m not sure “grit getting stuck there” is how I’d put it. It’s more like if you push an irregular object into sand, the sand will conform to the object, even as you move it.
 
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Well, if you are trying to correct subtle low spots, it’s good to have a flat stone with no mud. I’m not sure “grit getting stuck there” is how I’d put it. It’s more like if you push an irregular object into sand, the sand will conform to the object, even as you move it.
I was thinking of that approach as well. I will try that next time, and report results. I imagine choosing the right grit helps the cause. I have patience keeping a stone clean and flat for quite a while, but eventually has limits.

In course grits, I have Shapton pro (not glass) 120, 340, and Naniwa 400.

Also sandpaper, but not sure about how well it would do in this instance. I have a good flat/tight sandpaper holder, but somehow, a stone feels more precise.
 
I was thinking of that approach as well. I will try that next time, and report results. I imagine choosing the right grit helps the cause. I have patience keeping a stone clean and flat for quite a while, but eventually has limits.

In course grits, I have Shapton pro (not glass) 120, 340, and Naniwa 400.

Also sandpaper, but not sure about how well it would do in this instance. I have a good flat/tight sandpaper holder, but somehow, a stone feels more precise.
After looking at the blade, I am worried about issues B and C before undertaking this step. Not sure how to address that.

Also, the only double bevel I have to try this on is my Togashi Nakiri, which has little convexity. I can imagine "thickening" behind the edge first;-) But, that seems like a waste of metal, and maybe best to just use it until that happens naturally.

Wondering about a good knife to practice on.

All the ones I mentioned (1-5) have issues:
1 very thin and flat bevel and not much height left
2,5 mono-steel, 2 not worthwhile, 5 bent
3. see above
4. not interested in this one right now
 
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