Why can't you set a bevel off a finishing stone with high pressure?

[H Brad Boonshaft]

So, really the issue in this post has become, “Pressure”. Knife High Pressure and razor honing High Pressure are two very different things.

The mantra from some of the early Honing Video guys was, “Weight of the Blade” honing, to describe pressure. Well, that works for finishing a razor, but not for grinding out a chip. One could hone a razor with weight of the blade, but it will take a while.

If you use enough pressure to deflect the blade and lift the edge off the stone. that is too much, but you can certainly use much more pressure than weight of blade and keep the bevel flat on the stone.

Since the advent of Straight Razor fora. We have become stone/honing obsessed. There are folks that hone on multiple synthetic stone and finish on multiple natural grit combinations, then strop on multiple strops.

For hundreds of years folks have hone on a course stone and a fine stone and shaved just fine.

Any 8-12k will easily set a bevel and will not destroy/damage a razor or wear out your precious finisher. I only know a few guys that can wear out a synthetic finisher, and they are pro honers that use them daily, still they get decades out of them.

Bottom line, try it, you will be surprised.

 

[RayClem]

There is a video (well in two parts) on Youtube of someone who used the Suehiro Gokumyo 20K stone (0.5 micron) to one-stone hone an edge from bevel set all the way through shave ready finishing. It can be done, but it will take some patience.

As other have said, you do not want to use pressure when honing. You might use slight pressure in the early stages of the honing process. When finishing an edge, use the lightest touch possible that still keeps the bevel and the spine in contact with the hone. When finishing the edge, use pressure similar to that which you use when shaving your face.

 

[cotedupy]

Something not mentioned, if the edge flexes, and it will with surprisingly little pressure on a full hollow razor, the hone will scratch up the side of the razor above the bevel. You’ll see these scratches on razors if you look for them. It might be a good time to reiterate that a razor is not a knife and cannot be honed like one. I came to razors from Japanese knives, and TBH I would have been better off on razors not having any knife sharpening knowledge at all. Everything is bass ackwards on a razor; if it doesn’t cut well you can’t push harder, if the edge isn’t developing properly you use less pressure, not more, and so on. The only thing that knife sharpening and razor honing have in common is that you rub both of them on abrasives.

When I started with razors, I wondered why razor guys had all these coarse hones. Maintenance on a JKnife was 3-5k, and I rarely used the 1k. The reason is that you can’t push very hard on a razor, and if you’re doing chip removal or geometry correction you have to have coarse hones or you’ll spend the rest of your life fixing your razor.

Cost is another issue. Really fine stones that can finish a razor are expensive - a Shapton 30k is around $350. So why wear down a $350 stone when a $20 King will set your bevel just as well?

It's interesting how often people say this about knife vs razor sharpening...

*Personally* I think I was far better off coming to razor honing already knowing quite a lot about how bevels and edge geometry worked. The first razor restoration I did worked (slightly surprisingly) very well, and I hadn't been honing razors for very long at all at that point.

Though I had been idly browsing various razor forums for a while, so knew the technique and aims were different - if it hadn't been for places like this then I'm sure I would've been completely lost. I do also sharpen and restore quite a lot of single-bevel knives, and things like yanagiba actually work very similarly to razors.

But generally (I think) an understanding of how edges work is translatable. What you need to do is understand the differences, so comparison is useful; pretty much by definition it involves looking at things that are different... it's comparing things that are the same that's pointless!

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Just my 2c anyway... it's useful for me to think about things in this fashion, and to read yours and the various other answers .

 

[H Brad Boonshaft]

Well, you are probably very different from most “Knife” guys who have hone a Boy Scout knife or two and believe they know how to hone. You actually hone knives.

I venture to say most of us came to razors, from honing knives. The two are different but not that much different, and where Knife guys get in trouble is with pressure and understanding how to verify that the bevels are meeting fully.

I have taught a number of guys to hone, in person. Almost to a man their problems came from fear of using enough pressure to bevel set, fully.

The big difference between honing both is how to deal with a burr, a broken burr on most knives is no big thing but will draw blood on a razor.

When you hone a knife, skin comfort is not even a consideration, getting to sharp is easy, sharp, keen and comfortable is a the challenge for a razor. Hard to do if it is not on the radar.

Look at an edge from the side with magnification, now look straight down on the edge with magnification. Two very different perspectives.

Still, a year from now your razor edges will be vastly better than they are today, and so will you knife edges.

 

[Steve56]

I was referring to honing more than restoration, but certainly metal working and polishing skills translate. I also have a number of single bevel JKnives though I’ve come to prefer the symmetrical grinds better for Western cuisine.

The thing that makes a SR so much different is the extreme thinness of the edge and as mentioned above, a SR bevel is inclusive so a 16 degree SR bevel is an 8 degree knife bevel.

This has practical consequences. You see a good bit of Hitachi white paper #1 in better knives, but you never see it in razors - they used white #2 because it was more durable. As I understand it, Yasuki Y.S.S.H 2 is white #2.

If you push hard on a thinly ground razor, the edge will flex and the bevel will round and not develop properly. You have to hone the edge without it flexing which is why razor people have really coarse stones - you can’t push very hard on most razors.

The thinness also has manufacturing implications too. I’ve never seen a decent knife that wouldn’t take an edge. I’ve had some that wouldn’t hold an edge after opening an envelope but those were not decent knives. But you see razors that won’t take a high grit edge fairly often if many of them cross your bench. I have a beautiful 7/8+ Bartmann Manganese steel with a below 15 degree bevel angle. Without 2 layers of electrical to get it up around 17 degrees you’ll never get rid of the edge artifacts at finer grits and it doesn’t shave well. This razor is not properly made BTW, the spine is only 0.2” thick, it should be about 0.25” for a 7/8 razor.

Anyway, some knowledge and skills transfer but for the most part maybe not so much, especially honing.

 

[Steve56]

When you hone a knife, skin comfort is not even a consideration, getting to sharp is easy, sharp, keen and comfortable is a the challenge for a razor. Hard to do if it is not on the radar.

Lol, ‘A pot roast never complains.’

 

[Darth Scandalous]

I have a question regarding pressure. I've been thinking about it less as leaning on the razor and more about a slight torque biasing what pressure I am using towards the edge. I'm not sure if that's productive but it seems to be working for me. Obviously at the finer grit and finishing stages this is still a very light touch.

 

[bluesman 7]

If I was teaching someone who had never sharpened anything, my take would be 'OK this person probably has little experience using any hand tools and little 'feel' for using tools of any type'. Experience counts, even unrelated experience. IMO

 

[Steve56]

I have a question regarding pressure. I've been thinking about it less as leaning on the razor and more about a slight torque biasing what pressure I am using towards the edge. I'm not sure if that's productive but it seems to be working for me. Obviously at the finer grit and finishing stages this is still a very light touch.

Torque is good, light torque. It helps keep the edge in full contact, and if you’re honing without tape it helps keep wear off the spine.

Oddly, Iwasaki in his book chapter on barbering, may imply a slight torque when stropping. The English translation was by Jim Rion years ago and Iwasaki sometimes used archaic Japanese. If you’re interested, take a look at how he recommends holding the razor for stropping. I’ve tried it stropping with a hanging strop and it certainly doesn’t hurt anything.

 

[Slash McCoy]

What I regard as heavy pressure is the unsupported weight of my entire arm. I have never had to use more than that when working on a razor. By the time the bevel is fully set, I am usually at less than the weight of my hand, By the time I am at the 12k or 1u level, I am pretty much at just the weight of the razor. On the balsa I am not even using the weight of the razor.

 

[cotedupy]

I have taught a number of guys to hone, in person. Almost to a man their problems came from fear of using enough pressure to bevel set, fully.

This is an interesting observation I think, and happened to me on a couple of occasions early on when trying to restore razors.

I was being overly cautious, having read mostly about honing razors in terms of finishing stones, and went from a King 800/1200 to Kagayaki 3k, and found after that I hadn't set the bevel properly and had to go back. Luckily I checked properly after the 3k so didn't waste more time moving onto finishing stones, but yeah - that happened at least a couple of times.

 

[cotedupy]

This has practical consequences. You see a good bit of Hitachi white paper #1 in better knives, but you never see it in razors - they used white #2 because it was more durable. As I understand it, Yasuki Y.S.S.H 2 is white #2.

I'd always wondered about this... what Hitatchi steels do they use for kamisori? Are things like Aogami 2 and Super preferred...?

If you push hard on a thinly ground razor, the edge will flex and the bevel will round and not develop properly. You have to hone the edge without it flexing which is why razor people have really coarse stones - you can’t push very hard on most razors.

It was certainly points like this that I was wanting to know/understand about when I asked originally (and why I made the q. quite open-ended). I hadn't thought about flex at all tbh. Uraoshi sharpening for instance is very similar indeed to razor honing, but flex obviously doesn't come into it in the way it would with a razor.

 

[Steve56]

I'd always wondered about this... what Hitatchi steels do they use for kamisori? Are things like Aogami 2 and Super preferred...?

I’ve seen aogami (blue paper steel) razors, Takeshi at AFrames has some IIRC, but they tend to be ‘boutique’ razors. IME, aogami tarnishes and stains more quickly than shirogami, so possibly that’s why aogami isn’t used more in SR?

Shirogami also has a reputation for taking a finer edge than aogami, with aogami being ‘tougher’. On a knife this difference probably doesn’t matter until you’re in to high end or specialty knives.

You have to look at what they use and deduce why they’re using that steel, but here’s a useful reference.

YASUGI SPECIALTY STEEL | Products | Materials for tools and cutlery Searching for | Shirogami 2

Scroll down for the summary.

 

[Steve56]

Here’s an extreme example, a Paul Drees Sistrum, I have a Dreifuss that equally thin and flexible. These were made for the Italian market, whose customers wanted them to ring with a certain note.

I think that one can look at the image and see why that you can’t push hard on a fine stone to set the bevel! Image courtesy of ‘hatzicho’ at the Palace.

 

[Darth Scandalous]

I have a Helje MK 30 that wanted to flex every which way with minimal pressure. It was the razor that really solidified the idea of torque vs pressure in my mind, that I mentioned earlier.

 

[cotedupy]

Here’s an extreme example, a Paul Drees Sistrum, I have a Dreifuss that equally thin and flexible. These were made for the Italian market, whose customers wanted them to ring with a certain note.

I think that one can look at the image and see why that you can’t push hard on a fine stone to set the bevel! Image courtesy of ‘hatzicho’ at the Palace.

View attachment 1374591

Blimey... that is some serious flex, very interesting (for me anyway!)

 

[Steve56]

Blimey... that is some serious flex, very interesting (for me anyway!)

That image shows us the difference between a knife and a razor, lol.

 

[cotedupy]

That image shows us the difference between a knife and a razor, lol.

Haha yeah! And particularly the difference between monosteel vs san mai...

I can do something like this on a very short, hardened 1084 knife blade, and it'll just spring back because it's not clad:

 

[Steve56]

Haha yeah! And particularly the difference between monosteel vs san mai...

I can do something like this on a very short, hardened 1084 knife blade, and it'll just spring back because it's not clad:

View attachment 1374737

Who cares about the knife, wine and WD-40? You’re one of us!

 

[cotedupy]

Who cares about the knife, wine and WD-40? You’re one of us!

Proper ‘lubrication’ is essential at the sharpening station!