Criticizing Your Own Hand Work - a Knife in this case

[--Tom--]

I ended up doing this

Gave it a hard buff after, but the texture stopped any slipperiness.

You can get a laminated material made by ultex that has layers of rubber in - I used that for a big slicer and came out well

 

[--Tom--]

AEBL will take a nice edge, this was the slicer pre handle

The ultex handle material was a pain to finish, the rubber made it a bit smeary but grip was great.

 

[D_W]

AEBL will take a nice edge, this was the slicer pre handle




View attachment 143535
The ultex handle material was a pain to finish, the rubber made it a bit smeary but grip was great.

How do you surface finish the rubber part - a low speed buff? I'm guessing high speed buff will cause it to heat?

Knife looks great.

I think in an ideal situation, I can hit about 60 hardness with AEB-L with an open air heat and a fast quench into frozen plates after an initial quick dip in fast oil. A bit of a faff given a furnace and a dewar can hit 63 relatively easily with a 300-325 temper. I can't get close to that, but am surprised to get something relatively consistent at all out of the furnace.

The really interesting thing about it is it shows so little grain size under a microscope when used in a plane iron that the worn area looks like it's smudged - visually just nothing there to cast a shadow whereas seeing the carbides in other steels standing proud of the matrix is easy.

Just a dandy knife steel, even if I miss the target a little. will cut sticks and veggies and sticks and veggies back and forth without showing any ill edge effects from cutting the sticks. A very practical knife steel for someone who likes a fine edge but doesn't want something brittle.

 

[Fergie 307]

I'm not sure what they are called, but the folks doing the finish work generally follow something we'd consider to be a routine abrasive process, but with what used to be natural abrasives / fingerstones. The most traditional types probably wouldn't allow for much deviation.

The characteristics of the polishing stones (you can find terms like uchigumori) are to be progressive but not leave deep marks that will be seen later. there's another one that became the rage at the end of the time that I was buying and reselling (what I didn't want) japanese stones at cost to sting some of the dealers who were going past what I considered to be in good taste....it wasn't uchigumori but I got a request for it a lot. It was basically a 6k-ish knife finishing stone, and I never bought one and had to explain to a lot of people that it was for a task they weren't going to encounter.

I was using a fingerstone made for machinists, but almost cut the tip of my finger off with the boning knife here - I would *hate* to do the task on swords, but I guess one would get good at holding things from an end and in a direction where your fingers don't contact the knife. I flippantly was fanning the fingerstone back and forth and just got the tip of my finger in and cut off a half-pea sized amount that lucky stuck on by a hinge, I glued it back on and it looks like it'll be good to go!!

As nice as it is to work by hand, I think polishing something by hand would be kind of boring.

if there are swords made out of hand produced sand iron and finished traditionally, I wouldn't be surprised if they were several hundred thousand dollars.

I was intrigued that the makers mark was on the tang, so totally covered once the grip was in place. I recall reading years ago that an expert could recognise a sword made by a particular maker by the precise shape of the blade, and by the shape of the pattern left on the cutting edge, which in turn depended on the make up and application of the layers of clay used to control the hardening process. All closely guarded secrets of each maker, but almost like a fingerprint.

 

[D_W]

I was intrigued that the makers mark was on the tang, so totally covered once the grip was in place. I recall reading years ago that an expert could recognise a sword made by a particular maker by the precise shape of the blade, and by the shape of the pattern left on the cutting edge, which in turn depended on the make up and application of the layers of clay used to control the hardening process. All closely guarded secrets of each maker, but almost like a fingerprint.

We share this info so easily now, to the point that often it's shown and people don't think it's worth anything. It's such an interesting idea that makers would sit on something that's not that hard to do but may not be that easy to figure out when it's not offered trivially.

I've got no doubt that the makers had geometric preferences and aesthetics with the hamon (the line) size, intensity, pattern.

There is something about that "fingerprint" that is lost now. Not to mention that getting a defective blade made with such care would be extremely unlikely. The time involvement just to make things when you're doing them with the "leaves a fingerprint" method pretty much eliminates poor judgement in saving a minute here and there and ruining the result.

 

[--Tom--]

I’m not getting aebl as hard as I want, best I’ve managed is 60 but often tester reads 57-59. Carbons I can repeatable hit target hardness within a point getting 63/64. Thinking it’s decarb during soak, but edge is more prone to fold at acute angles when brass rod testing. Have done both plate quench and oil first then plates - spec chart shows shouldn’t make a diff as have a while to get the temp down.

Are you using any decarb wrap/paint or just running a reducing atmosphere? Any soak time?

 

[cotedupy]

AEBL will take a nice edge, this was the slicer pre handle




View attachment 143535
The ultex handle material was a pain to finish, the rubber made it a bit smeary but grip was great.

I really like that handle, great job.

I used to work in the wine/restaurant biz for quite a while and kitchens overwhelmingly use rubber/ plastic handled knives. Downside being that they usually look like c***. Yours is great though .

 

[cotedupy]

I was intrigued that the makers mark was on the tang, so totally covered once the grip was in place. I recall reading years ago that an expert could recognise a sword made by a particular maker by the precise shape of the blade, and by the shape of the pattern left on the cutting edge, which in turn depended on the make up and application of the layers of clay used to control the hardening process. All closely guarded secrets of each maker, but almost like a fingerprint.

I've got no doubt that the makers had geometric preferences and aesthetics with the hamon (the line) size, intensity, pattern.

It's certainly very much the case for honyaki knives and katana that particular makers will have a distinctive hamon style. There's one very famous one which is the 'Moon Over Mt. Fuji', where the Hamon looks like the outline of the mountain and a crescent moon is usually etched on the blade after. It's done by quite a few different people, but there's one maker in particular (I forget his name) who can produce blades where the moon itself is part of the hamon, with the bottom of it just kissing the top of the mountain.

My understanding of tang stamps is that they tend to refer to the individual person who has done the grinding / sharpening, and is the result of some quirks of the production and sale of Japanese knives... Some makers will have various different people doing it. Or if a producer has been going for a number of generations, to distinguish between father and son. Or sometimes the kanji on the main part of the knife may be that of the retailer, and it's only by looking at the tang that you can know who actually made the knife.

 

[D_W]

I’m not getting aebl as hard as I want, best I’ve managed is 60 but often tester reads 57-59. Carbons I can repeatable hit target hardness within a point getting 63/64. Thinking it’s decarb during soak, but edge is more prone to fold at acute angles when brass rod testing. Have done both plate quench and oil first then plates - spec chart shows shouldn’t make a diff as have a while to get the temp down.

Are you using any decarb wrap/paint or just running a reducing atmosphere? Any soak time?

From the charts I've seen, it has a retained austenite problem. I try to do something simple with each steel, and can get book results on anything simple (combination hardness and toughness) and good grain size. Stainless, I usually end up a little soft, but because I'm in the open atmosphere (no wrap, no paint) I try to bias things that create higher hardness, not necessarily what's normally done for stainless. So a quick really high heat, and AEB-L will or XHP will generally be very hot for some large fraction of a minute.

So, there's no full normalization like a furnace, but I think it's a little more forgiving of error than a soak, where the soak can either create something really good, or it can be off in either direction (not hot enough or too hot) and really affect the amount of carbon in solution and retained austenite.

The only thing I can glean from Larrin Thomas's charts is that liquid nitrogen right after the quench will cover up a whole lot of issues with AEB-L. My issue in the open atmosphere ignores all of that stuff - what I do is pretty simple:
1) heat the steel to a high temperature, then quench faster than it would need to be soaked
2) it hits plates between the beginning and tail of the quench to stay straight if it's a knife. XHP doesn't really move. AEB-L seems to be more willing to move, but it's not like 1084 in terms of movement. The tail of the quench is a complete dip in water and then toss the knife in the freezer
3) if I have an offcut, especially of carbon steel, I will experiment in quench heats and various things because it's really quick in a forge, and note the relative color change after nonmagnetic where grain grows, and then I will shrink that back
4) the last thing will be a wear test in a plane iron, which will allow me not to see the grain size, but it will allow me to see the size and dispersion of carbides. If they are nice and relatively round and evenly dispersed - good.

Fast cold quench will deal with some of the R.A. problem but liquid nitrogen would help a lot more. If I ever get a furnace, not sure I will at this point because of the space and the time it adds to everything, then I will also probably get a dewar.

As it is, it's not a great plane iron steel (AEB-L) for some reason - it's got good edge life, but other steels cut better as they dull, even if they don't last as long. And if I can reach the 58-60 range with knives and at least get something noticeably better than 420HC for edge holding, then that's OK.

Fast cold quench for carbon steels is just about magic, especially if they have a lot of surplus carbon.



These are samples that I sent to larrin thomas for testing. I had already done my due diligence snapping samples and shrinking grain. O1 is about where book says it should be. Some charts show a little more toughness. 26c3 is off the chart. I think a fast heat prevents too much carbon from getting into solution, and a fast quench still picks up the tail end and keeps the carbon at book. These sample are all done individually, and the tempering is all done at the same time between plates in a toaster oven, double tempered around 400F, give or take toaster oven fluctuation - which is a big fluctuation, but inside the mass of scrap steel, only bobs around a degree or two F according to the thermocouple that I have in the middle of the stack.

The idea that 26c3 does better with minimal thermal cycling and then a high heat by eye is generally not well received (I got banned from a knife forum for thinking this should be looked at further, but those forums can be weird with "do it my way" people). I lost track of one O1 sample in the forge and it got heated a little too long but I quenched it and sent it, anyway. I think that's the flyer. At any rate, with nothing more than parks 50, some cold water and a freezer, I'm getting high hardness (above book) and good toughness. A dewar of LN would increase things even further.

It's a great steel for chisels. Great. Sharpens like it's softer than it is but chisels like a hard steel and takes a fine edge off of almost anything.

 

[D_W]

I’m not getting aebl as hard as I want, best I’ve managed is 60 but often tester reads 57-59. Carbons I can repeatable hit target hardness within a point getting 63/64. Thinking it’s decarb during soak, but edge is more prone to fold at acute angles when brass rod testing. Have done both plate quench and oil first then plates - spec chart shows shouldn’t make a diff as have a while to get the temp down.

Are you using any decarb wrap/paint or just running a reducing atmosphere? Any soak time?

I've got samples out of the forge of AEB->L now that can't be cut by a good file.

I mentioned earlier in another thread that at typical forge heat, I think it's tough to get 2000F tool temperature, which is a slight overshot of the actual heat target for AEB-L.

What I've found with any steel that has something that will limit grain growth (that can be either chromium or vanadium or both) is that if no soak is involved, an overshot will get you to about the same place, but it takes experience to figure out what.

I think once you figure out "what" the overshot has fewer issues with retained austenite - I don't know exactly why.

For folks who don't want to look up retained austenite, heat treating is described as complicated with a soak for a lot of steels because the soak time and temp create the make-up of the steel before quenching. If there's not enough austenite, then the result won't be that hard (and could be unstable). if there's too much, then all of it won't be converted in the quench, and the result won't be that hard.

I showed the banana slicer in another thread:


if the point is to make a good banana slicer that won't suffer edge damage in any normal use, or even abnormal stuff like cutting sticks, it's fine.

But I'm irritated that i can't break the rules and push hardness up into the 60+ range because AEB-L itself should be a steel that doesn't have anything that needs to be normalized in it, just like a high quality PM probably has been rolled to a condition suitable for a high heat and a good result.

Just for mention to Tom - Larrin suggested a pre-quench and then a heat of 1900-ish for 15 minutes. if I get somewhere near that, I don't get the hardness that he shows (make sense, I'm not soaking anything for more than the time it takes it to get really hot because I don't want to wrap).

But yesterday, i configured my longer knife forge and am making an insert for it to concentrate heat so I can hit an overshot quickly and then just quench with as fast of a quench as possible ending after the fast oil quench to frozen plates.

The quench result must be in the mid 60s and no sign of decarb on the corners. the only thing left to do is finish grinding the knives and make sure the results is through and through.

I found the same thing on plane irons - the heat has to be fast and really hot, not propane hot but not yellow. The difference with a plane iron is the area to be heated is so small that you can concentrate all of the forge heat to one spot and do this. without the overshot, the hardness just isn't there and I just don't have much interest in buying a furnace because I don't want to be tied to waiting for it to do its thing. The process of a fast pre-quench and this high heat shot is a couple of minutes. no wrapping, etc and I can't practically get to an overshot so high that it would create an excess austenite issue like an overtemp soak does.

 

[D_W]

Just sweeping back around - both knives are hard through and through - I would guess 61/62 hard but not sure. I'll play a game with some offcuts of cutting a bevel and testing strength against known hardness steels.

Grinding the higher hardness AEB-L is a lot slower than high hardness carbon steels, too - when it's in the assumed high 50s, it grinds easily.

While it's been nice to get it high hardness without buying a furnace, I'm not sure I see the need day to day - there's a sweetness to it in the high 60s and knife geometry dominates when you can buff off the apex and avoid edge rolling at lower hardness.

 

[cotedupy]

Just sweeping back around - both knives are hard through and through - I would guess 61/62 hard but not sure. I'll play a game with some offcuts of cutting a bevel and testing strength against known hardness steels.

Grinding the higher hardness AEB-L is a lot slower than high hardness carbon steels, too - when it's in the assumed high 50s, it grinds easily.

While it's been nice to get it high hardness without buying a furnace, I'm not sure I see the need day to day - there's a sweetness to it in the high 60s and knife geometry dominates when you can buff off the apex and avoid edge rolling at lower hardness.

What grinder do you use D?

Variable 2x72s seem popular in the knife world...

 

[D_W]

What grinder do you use D?

Variable 2x72s seem popular in the knife world...

They definitely are - multiples of them in a shop.

I use a jet IBG-8 grinder (rather a pair) - and a slightly upgraded 4x36 belt sander. One of the jet grinders has a 2x48" belt with a platen and 8" contact wheel, so I am going spartan compared to a knife maker who wants to set up jigs and be able to mindlessly run knives through. I want more of a freehand look and the ability to do complex shapes on handles by eye, like this micarta handle (keep in mind, I'm a beginner at making handles generally just with a contact wheel and slack belt side, but it's coming together relatively quickly.

boils down to me being minimally equipped compared to someone making runs of knives. The contact wheel is what I need to cut bevels on hardened chisels, high speed and ceramic belt, without drawing temper. I don't do much platen work, which is good, because the platen on the attachment that I got (multitool) is one of the worst I've seen. It's under the belt as a suggestion and not similar to a good 2x72 grinder with the belt drawn snug.

 

[TRITON]

Couple of things to take note of in a boning knife.
1. Not too long. 6" as a max, but 5" is better for control.
2. The knife will be bending in use, especially separating the joints in the beef shoulder. So too thin it could snap or even retain a bent shape.
3. For sterilization purposes it should always have a handle you dont mind putting through a dishwasher.

Love watching this guy work.

Meh

(As in a professional Meh )

 

[D_W]

Couple of things to take note of in a boning knife.
1. Not too long. 6" as a max, but 5" is better for control.
2. The knife will be bending in use, especially separating the joints in the beef shoulder. So too thin it could snap or even retain a bent shape.
3. For sterilization purposes it should always have a handle you dont mind putting through a dishwasher.


Meh

(As in a professional Meh )

Thanks - this last one is about 6" blade to end, but the handle is smaller than the big rubber consumer types. It's clear holding it (I slightly adjusted a pattern I found on the web) that it's intended to be used for delicate work holding with fingertip on top of the knife spine. It's reasonably comfortable holding like stabbing hold, but the person getting it will want to scuff the micarta - he's welcome to do whatever he wants as long as he tells me if it breaks and how he broke it.

The tip is thin and short in height -would not be a good consumer knife as it would be toast or at least bend the tip would bend. The micarta handled knife is chisel hardness - the other ones were a bit softer. All have good flexibility, but the latter is much stiffer. The steel type is AEB-L, which is about the toughest steel I can find that still holds a decent edge. If you're into knives, it's kind of a parallel to 3V, but stainless (both are matrix steels - not enough carbon to form large carbides).

The consumer versions of these knives tend toward something like 420hc, which is ultra tough (easy to bend, hard to break cleanly and not make it look like the fault of the user) or if they are something hard, the knife pattern gets much more stout.

Knife market is an interesting thing. Some of the production knives actually look pretty nice. They do seem to make interesting claims about hardness and probably come up a few points short. Then there's a lot in the middle, like weird shaped parers that are just fast jig ground with $200 price tags, but if you look through the details, they're something like Elmax without any hardness spec given - I think this is the mark of the steel pushing in the knife world - that a knife with probably $20 more steel can sell for more than $100 more than it would bring with something more pedestrian. The buyer will have no idea that the geometry is strange, but maybe the average buyer doesn't care about that. I'm assuming that most moderate and higher cost production knives and moderate cost semi-custom knives are relying on recommendations from cooking shows and magazines to be seen as a good gift. .


almost forgot - some of the better edge taking stainless steels will stain just a little bit with certain foods. People understand what color things are and whether or not they can get them perfectly clean. AEB-L is an excellent steel. But it's on the lower end of stainlessness and I could imagine the lower carbon stainless steels (in the 0.3-0.4% carbon range) will please buyers even if they're not that great, because they are hard to stain.

 

[TRITON]

The knife below is probably the most used knife in the meat trade. Costs between £12-£15.(Cost £4 when i first bought mine, some 30+ years ago.)
It's not fancy, I dont think its made of a steel anyone will rave about, and its not pretty to look at. But it does the job, and does it consistently for a number years.
Like all actual trade/pro stuff its dependable though expendable tool.

Unfortunately i seem to gravitate towards knives like this for home use, rather than spend huge amounts of classier offerings, though I did for my sisters wedding gift buy the lucky couple a set of 3 Gustav Emil Ern(7" cooks, bread and 4" parer)
I also bought a friend, who was a vegetarian (along with his wife) an F.**** 3.5" paring knife, for them to do their veg with, and despite all the other wonderful gifts they received,I suspect mine was the one they liked most, because when they unfortunately divorced, apparently there was a custody fight going on as to which one got the knife

 

[D_W]

I only have a black outline for the boning knife I made first - as in, a picture that the owner took but the lighting was bad enough that I couldn't tell what it was. I think it's probably that knife or something similar.

The issue for the owner was how fast the tip wears - it bugs him to have to stop boning a deer to sharpen twice per deer.

I probably summarized already, I could make him a knife either that would sharpen better, or that would resist abrasion enough to still be cutting well all the way through a deer. Time will tell. Since I don't butcher, I asked him about it, and he referred to "ideally it should be more like a surgeons tool".

That knife you pictured looks like one that could have the edge aligned or sharpened really quickly - I worked in restaurants as a kid and never found what people would consider a nice knife - that was before the liability limitation that's gone on now - some restaurant chains don't allow use of knives and the food comes in mostly prepared and is just assembled. The manager dealt with our knives at one of the restaurants, so I don't know what was actually done, but the parers were disposable and the bigger knives probably went out to a service.

The knife pattern you show is just about ideal to crank out knives and do it profitably. It's probably something like a 0.2 or 0.3% carbon stainless steel that blanks well and doesn't warp, and then the handle is moulded around it.

And it works and always will and if it doesn't, you don't have to feel like it's precious while using it.

I don't think I'd ever get to a point where I'm selling knives, just enjoying seeing if they can perform better when consumer and commercial suitability go out the window.

Separately, I found a supplier of .04" AEB-L this week, and am interested in making some small parers that have good hardness but are very thin.

originally, I didn't want to make stainless knives because I wanted something that sharpens like a chisel, and AEB-L has a lot of toughness and chromium - it gets to an easy edge of clean hair shaving, but there's something about 80CRV2 and how easily it does the same that's really a draw.

.....until it rusts.

https://www.bladeforums.com/threads/420hc-toughness.1796429/
The top chart on this page shows where 420HC is. These charts are from larrin thomas, and the focus isn't really on consumer knives, so to the left of the chart would be 55 hardness steels that are flexible and not great for holding an edge, but would be super hard to break. It's interesting when going backwards into the very inexpensive blanking steels (aeb-l is also a steel that blanks well) just how low the carbon % can be as I considered 0.67 in AEB-L to be really low. the far end of the chart on the right is very high abrasion resistant steels that are popular now - they last 50% longer than AEB-L and the transition metals (almost carbide) can get double, but nobody has come up with a solution for carbide volume and what it does to toughness - so for boning or daily parer, those knives would have little chance of an "honest return" (having to hone out only dullness vs. chipout).

I have a knife in SG2 that someone recommended to me - it's abhorrent on sharpening stones. It's not so much that it's abrasion resistant, but that the toughness is so poor that it will not take a fine edge off of anything other than the buffer. It does do well when you do things like scraping metal and sharpness goes out the window. I guess that's the value of the carbides resisting abrasion from the metal to metal contact.

I find this stuff fascinating - I'd be handing out free or near free knives here if you guys were in the states. What else can you do with all of your stuff.

Back to the consumer knives, though - I'm loathe to talk like the folks who show something fine and say you can't work with something cheap. That's H.S. I worked over the last several years to come up with fast sharpening methods that will work on subpar steels and it's hard for me to make a case for the need for any expensive knives at all. Those blanked knives can normalize in 5 minutes and air quench and temper once and be ready for whatever it takes to get a packed knife out to retailers. It's really hard to criticize that. The types like 420HC are completely devoid of any large particles - they really are good stuff once one learns to deal with the burr and modify the apex. I have a buck 420HC pocket knife that I "unicorned" over and until someone notified me "there's a tool for that", I was using it to chamfer the insides of the brass ferrules for chisels.

...but this hack maker needs something to do once in a while.

 

[D_W]

By the way, I mentioned a $200 very crude parer that I saw yesterday - big tall short stubby blade, heavy looking knife - Elmax.

I see where Elmax is on that chart. There may be something i don't know about it, but low hardness and low toughness - it can become difficult to get good edge life out of a high abrasion resistance knife that can't also go high hardness to prevent the apex from being distorted. Lamson in the US sells a bunch of nice basic knives for about $50 each that are 58 hardness 420HC - US made (no doubt in automatic grinding fixtures). I know which one I'd rather have.

 

[TRITON]

it bugs him to have to stop boning a deer to sharpen twice per deer.

Well he should really be putting the knife on a steel multiple times while working. Though maybe his expectations are too much on how exactly it needs to be edge wise. Deer bones are quite soft, so too sharp, as in razor edge it just catches on them. I suppose thats something you learn about while working, might not be obvious to the home user, but I'd never use the above knife fresh out the packet without blunting it slightly first.

 

[D_W]

I think he's hoping for a knife that's too hard to steel - I didn't ask too much. I just said I was surprised that stainless would abrade that easily and wanted clarification about whether some of the issues were deformation. He looked closer and whatever's in the whitetail deer here, it's abrasion on the tip.

The steel vs. note is a whole other debate. I have no real preference either way as long as people don't steel knives not meant to be steeled or complain that knives that are intended to be steeled don't hold a 1 micron stone edge very long.

In my house, steeling isn't practical because my wife does most of the knife use with everything other than the chef's knife and she refuses to steel a knife and the damage is too much too fast to bring it back with one. A stoned edge tests better here - it can be tolerable for about a month. for whatever reason, I guess because we don't put knives in the dishwasher, nicking is minimal.

All of the knives that I've shown here along with a very thin bevel chef's knife - all are banned from the kitchen, which is fine. That means when I pull them out of my desk and go to make something, there's no surprise.