4 ms·

Cooks use a knife straightener on their knives to keep them sharp longer. Well, I'm not a cook, but I do it too. It works really well. I was wondering if people

by gpsx 6y ago

Cooks use a knife straightener on their knives to keep them sharp longer. Well, I'm not a cook, but I do it too. It works really well. I was wondering if people could do this on razors. I think this is equivalent to palm stropping. For a cartridge, I think something with small metal teeth, at the right angle, ran back and forth over the blades, would do a good job of straightening the edges.

wahern 6y ago
I suspect cartridge and safety razor blades are too hard (e.g. martensitic or carbide; see https://en.wikipedia.org/wiki/Razor_blade_steel https://en.wikipedia.org/wiki/Razor_blade_steel) and too sharp for stropping. That's probably why they're more prone to chip rather than deform. A good straight razor is made from a softer carbon steel that, while harder than most stainless steels, isn't quite so brittle. And the edge isn't as 'razor sharp' as safety and cartridge blades, but more rounded. I shave with a straight razor, but I'm lazy and use a Feather with disposable blades. Before that I used aluminum hair shaper blades, like what the barber uses on the back of your neck (very sharp and thin, but an aluminum alloy). Such blades are far sharper than a real straight razor and cause razor burn more easily. I always sort of suspected as much. I tried using a traditional straight razor several times, but I couldn't get used to it. The feel is just too different. Several years ago I popped into a barbershop where the owner did a lot of traditional straight razor work (very rare these days), and he confirmed everything--a traditional straight razor has a softer, rounder edge--and disposable blades, like my Feather blades, are far too sharp in his opinion. For similar reasons, thinner, harder blades are more likely to nick you because the microscopic chips tear into your skin more easily. By contrast, as a traditional straight razor gets dull it stops working as well but doesn't become more dangerous. Same thing applies to chef knives. You can use a "steel" on Western knives because the metal is traditionally softer and has a blunter profile and edge. (If it's a cheap stainless pressed steel, not uncommon in typical commercial kitchens--neighborhood joint, not Michelin--you can literally feel the edge rolled over on a dull knife, which steeling rolls back.) A traditional Japanese knife is more like a straight razor blade--harder steel, thinner profile, sharper edge which you maintain with a strop and waterstone--but still softer and blunter than manufactured razor blades. A cleaver, Western or Asian, is supposed to be very hard (often a cheap but very high carbon steel) but also very blunt. You can't steel or strop it; when it gets too dull you have to grind it or, if you have time to kill, resharpen with a stone. (Confirmed with a Chinese butcher years ago.)
- aaron695 6y ago
  Electronic microscope of a Gillette Fusion blade pre and post stropping https://nanofabrication.tumblr.com/post/145006851641/ever-wonder-what-stropping-a-cartridge-razor https://nanofabrication.tumblr.com/post/145006851641/ever-wo... No idea if it means they are sharper or last longer though.
  - wahern 6y ago
    It doesn't look like it's doing anything except removing skin detritus, which is what I'd expect. Interesting pics, though.
- KozmoNau7 6y ago
  A steel doesn't roll back a folded over edge, it removes material and sets a micro-bevel. It's similar to stropping, but with a hard metal tool rather than a soft leather/denim fabric impregnated with paste. And it's easier to mess up and dull your knife instead, a knife in reasonable condition really shouldn't need more than a couple of light strokes on the steel on either side. Conversely it's almost impossible to over-strop a knife as long as you don't completely mess up the angle and use too much pressure. In short, everything you do to work on a knife edge removes material. The difference is in how aggressively it does it, and to which angle. If the edge on your knife keeps rolling over or creating a burr just from using it, you're sharpening it to an angle too acute for the steel to properly support. In my experience, by far the most important tool is the strop. I can get dull knives shaving sharp with a 240-grit stone and a strop in a couple of minutes, though usually I take my knives to 3000, because it's easier on the strop.
  - wahern 6y ago
    Stropping definitely doesn't remove material. It heats the edge which aids in deforming it back into a more preferable shape as you press into the material (leather, canvas). If material was removed it'd embed in the strop and damage your edge, either by chipping or just uneven action. A strop with paste is a different beast, IMO. You didn't traditionally use a paste with stropping. I'd bet the rise of pastes, which seem kind of gimmicky, is related to a loss of traditional expertise and knowledge about the function of the strop. Relatedly, because of the rise of safety and cartridge razors, people are accustomed to extremely sharp edges. A traditional straight razor shave feels harsher--more pressure and pulling--than people expect. Utterly unrealistic depictions on TV and film don't help, either. For years I thought I just really sucked at sharpening and honing my traditional straight razors (one of which is a very expensive Thiers Issard given as a gift), but after several traditional straight razor shaves at barbershops, which were consistently harsher than the hairshaper and Feather I normally use, and the discussion with that one barber who was an expert on straight razors, I realized it wasn't my poor blade sharpening skills--well, not just my poor skills. Traditional straight razors just were never meant to be as sharp as manufactured, disposable blades, and can't be unless you want to spend more time maintaining the blade than actually using it. Similarly, if you're constantly removing material the blade won't last very long as it depletes beyond a useful profile. Contrast that with wood planes and chisels, which tend to have very deep, thick profiles because of the need for more frequent sharpening and material removal; you need that depth so the angle of attack diminishes less as it shortens, otherwise you'd need to compensate with a more fragile bevel, which would just accelerate the process. Steeling might remove some material, especially when used on harder steels, but in the particular case of pressed stainless I don't think so. (But would be happy to see evidence to the contrary.) Traditional stainless steels (not new alloys with, e.g., molybdenum) are relatively soft. It's part of the reason why they're considered more resilient than traditional steels. They tend to have higher shear and tensile strength than non-hardened steels; they'll deform more before they break so they absorb energy better. So, for example, a stainless steel screw is closer to the resiliency of nails in terms of sheer strength than regular screws. Moreover, a pressed knife almost by definition needs to be made of relatively soft metal. One of my first jobs was working in a kitchen where we used horribly cheap pressed stainless knives for preparing chicken strips. After slicing a bag of chicken breasts you could actually feel the edge rolled over, like a letter J. (EDIT: rolled over is a poor description; if it were completely rolled over deformation by steeling would never work given the direction of the stroke. Note that the letter J isn't upturned on my font.) We'd always have to steel the knifes at least once or twice a shift. If steeling removed that material you'd have metal burrs everywhere, including in your food. Maybe steeling traditional Western chef knives does remove material. But if so I wouldn't be surprised if the benefit is in tearing the edge, effectively making a micro-serrated edge that works better than an otherwise dulled edge. Still, I'm dubious that's the primary function if it is at all. Everything I've read and experienced (as a home cook, at least) is that Western knifes traditionally use softer steel, and steeling is for deformation/reformation of the edge without removing material.[1] Steeling a traditional Japanese knife, or especially a straight razor, is verboten because of the potential for chipping, macro or micro. I'd never shave with a straight razor that had been steeled, though I confess I've never tried that specifically. That said, I admit the purpose and mechanical action of steeling is debated. I see conflicting discussions (not formal material) all the time, including from professional chefs, and I try not to discount people's experiences. Plus, it's not uncommon for the reality of something to differ than the theory even when the same result (e.g. easier cutting) is obtained. And times have changed. Modern alloys have different properties than traditional steels, so it's entirely possible the steeling action is different on many newer knifes than older ones. [1] Indeed, IIUC, the very conclusion of the research article suggests that if steeling worked by cutting material rather than deformation, you'd end up with significant microchipping and by definition a less sharp and uniform edge.

by gpsx 6y ago

wahern 6y ago

I suspect cartridge and safety razor blades are too hard (e.g. martensitic or carbide; see https://en.wikipedia.org/wiki/Razor_blade_steel https://en.wikipedia.org/wiki/Razor_blade_steel) and too sharp for stropping. That's probably why they're more prone to chip rather than deform. A good straight razor is made from a softer carbon steel that, while harder than most stainless steels, isn't quite so brittle. And the edge isn't as 'razor sharp' as safety and cartridge blades, but more rounded. I shave with a straight razor, but I'm lazy and use a Feather with disposable blades. Before that I used aluminum hair shaper blades, like what the barber uses on the back of your neck (very sharp and thin, but an aluminum alloy). Such blades are far sharper than a real straight razor and cause razor burn more easily. I always sort of suspected as much. I tried using a traditional straight razor several times, but I couldn't get used to it. The feel is just too different. Several years ago I popped into a barbershop where the owner did a lot of traditional straight razor work (very rare these days), and he confirmed everything--a traditional straight razor has a softer, rounder edge--and disposable blades, like my Feather blades, are far too sharp in his opinion. For similar reasons, thinner, harder blades are more likely to nick you because the microscopic chips tear into your skin more easily. By contrast, as a traditional straight razor gets dull it stops working as well but doesn't become more dangerous. Same thing applies to chef knives. You can use a "steel" on Western knives because the metal is traditionally softer and has a blunter profile and edge. (If it's a cheap stainless pressed steel, not uncommon in typical commercial kitchens--neighborhood joint, not Michelin--you can literally feel the edge rolled over on a dull knife, which steeling rolls back.) A traditional Japanese knife is more like a straight razor blade--harder steel, thinner profile, sharper edge which you maintain with a strop and waterstone--but still softer and blunter than manufactured razor blades. A cleaver, Western or Asian, is supposed to be very hard (often a cheap but very high carbon steel) but also very blunt. You can't steel or strop it; when it gets too dull you have to grind it or, if you have time to kill, resharpen with a stone. (Confirmed with a Chinese butcher years ago.)

aaron695 6y ago
Electronic microscope of a Gillette Fusion blade pre and post stropping https://nanofabrication.tumblr.com/post/145006851641/ever-wonder-what-stropping-a-cartridge-razor https://nanofabrication.tumblr.com/post/145006851641/ever-wo... No idea if it means they are sharper or last longer though.
- wahern 6y ago
  It doesn't look like it's doing anything except removing skin detritus, which is what I'd expect. Interesting pics, though.
KozmoNau7 6y ago
A steel doesn't roll back a folded over edge, it removes material and sets a micro-bevel. It's similar to stropping, but with a hard metal tool rather than a soft leather/denim fabric impregnated with paste. And it's easier to mess up and dull your knife instead, a knife in reasonable condition really shouldn't need more than a couple of light strokes on the steel on either side. Conversely it's almost impossible to over-strop a knife as long as you don't completely mess up the angle and use too much pressure. In short, everything you do to work on a knife edge removes material. The difference is in how aggressively it does it, and to which angle. If the edge on your knife keeps rolling over or creating a burr just from using it, you're sharpening it to an angle too acute for the steel to properly support. In my experience, by far the most important tool is the strop. I can get dull knives shaving sharp with a 240-grit stone and a strop in a couple of minutes, though usually I take my knives to 3000, because it's easier on the strop.
- wahern 6y ago
  Stropping definitely doesn't remove material. It heats the edge which aids in deforming it back into a more preferable shape as you press into the material (leather, canvas). If material was removed it'd embed in the strop and damage your edge, either by chipping or just uneven action. A strop with paste is a different beast, IMO. You didn't traditionally use a paste with stropping. I'd bet the rise of pastes, which seem kind of gimmicky, is related to a loss of traditional expertise and knowledge about the function of the strop. Relatedly, because of the rise of safety and cartridge razors, people are accustomed to extremely sharp edges. A traditional straight razor shave feels harsher--more pressure and pulling--than people expect. Utterly unrealistic depictions on TV and film don't help, either. For years I thought I just really sucked at sharpening and honing my traditional straight razors (one of which is a very expensive Thiers Issard given as a gift), but after several traditional straight razor shaves at barbershops, which were consistently harsher than the hairshaper and Feather I normally use, and the discussion with that one barber who was an expert on straight razors, I realized it wasn't my poor blade sharpening skills--well, not just my poor skills. Traditional straight razors just were never meant to be as sharp as manufactured, disposable blades, and can't be unless you want to spend more time maintaining the blade than actually using it. Similarly, if you're constantly removing material the blade won't last very long as it depletes beyond a useful profile. Contrast that with wood planes and chisels, which tend to have very deep, thick profiles because of the need for more frequent sharpening and material removal; you need that depth so the angle of attack diminishes less as it shortens, otherwise you'd need to compensate with a more fragile bevel, which would just accelerate the process. Steeling might remove some material, especially when used on harder steels, but in the particular case of pressed stainless I don't think so. (But would be happy to see evidence to the contrary.) Traditional stainless steels (not new alloys with, e.g., molybdenum) are relatively soft. It's part of the reason why they're considered more resilient than traditional steels. They tend to have higher shear and tensile strength than non-hardened steels; they'll deform more before they break so they absorb energy better. So, for example, a stainless steel screw is closer to the resiliency of nails in terms of sheer strength than regular screws. Moreover, a pressed knife almost by definition needs to be made of relatively soft metal. One of my first jobs was working in a kitchen where we used horribly cheap pressed stainless knives for preparing chicken strips. After slicing a bag of chicken breasts you could actually feel the edge rolled over, like a letter J. (EDIT: rolled over is a poor description; if it were completely rolled over deformation by steeling would never work given the direction of the stroke. Note that the letter J isn't upturned on my font.) We'd always have to steel the knifes at least once or twice a shift. If steeling removed that material you'd have metal burrs everywhere, including in your food. Maybe steeling traditional Western chef knives does remove material. But if so I wouldn't be surprised if the benefit is in tearing the edge, effectively making a micro-serrated edge that works better than an otherwise dulled edge. Still, I'm dubious that's the primary function if it is at all. Everything I've read and experienced (as a home cook, at least) is that Western knifes traditionally use softer steel, and steeling is for deformation/reformation of the edge without removing material.[1] Steeling a traditional Japanese knife, or especially a straight razor, is verboten because of the potential for chipping, macro or micro. I'd never shave with a straight razor that had been steeled, though I confess I've never tried that specifically. That said, I admit the purpose and mechanical action of steeling is debated. I see conflicting discussions (not formal material) all the time, including from professional chefs, and I try not to discount people's experiences. Plus, it's not uncommon for the reality of something to differ than the theory even when the same result (e.g. easier cutting) is obtained. And times have changed. Modern alloys have different properties than traditional steels, so it's entirely possible the steeling action is different on many newer knifes than older ones. [1] Indeed, IIUC, the very conclusion of the research article suggests that if steeling worked by cutting material rather than deformation, you'd end up with significant microchipping and by definition a less sharp and uniform edge.