drmoss_ca
Is there a Doctor in the house ?
Those of us who hone know perfectly well that some razors are easier than others, with a wide range such that some razors just need to be waved in the general direction of any old hone and they get sharp, while others can take you days of sweat and tears as you labour over multiple hones and pray to the razor gods to release you from bondage.
I expect that different issues come into play at various points in that range. I'd expect that softer vintage Sheffield steel will make a razor easier to hone, and over-hardened HRC66 steel will take a lot longer. And perhaps not just hardness, but toughness and other metallurgical qualities.
Then there are the difficulties caused by odd designs like a massive smile. Geometry comes into it rather obviously for the very difficult to impossible razors. But if we ignore the extremes of material science, design and geometry, we are dealing with 90% of razors that sit somewhere in the middle.
I'm wondering if small errors in geometry - really small - make the differences among most razors? When you grind by eye, there are limits to the tolerances you can achieve. I'm not a razor grinder, but I know what has to be achieved, and it looks something like this:
(Assuming you have hardened and then tempered the blade blank without inducing any warping)
1. Constant width of spine from one shoulder to the shoulder on the other side, and each shoulder must be perfectly flat in plan view.
2. Constant distance from one shoulder of the spine to the edge, and precisely the same constant distance on the other side.
3. A perfectly straight edge, in elevation, is required to allow the above.
4. The edge must be perfectly centered, in plan view, between the shoulders of the spine.
5. Even with all the above true, the razor must have no side to side curve along its length.
That's an awful lot to ask, and it obviously comes down to acceptable tolerances. Let's say you are an experienced razor grinder, and you have ground thousands of razors eight hours a day, five days a week for decades. Nearly all the razors you turn out will be serviceable, but there will be inevitable variation. A few thou here and there that might account for the difference between a razor being easy or hard to hone. Is it the case that only egregiously bad grinding makes a razor incapable of being honed, and that the stones simply remove a little more metal here and there to cover up the sins of the tired grinder?
Think of this - if you buy a pair of razors for a travel set. Same make, model and bought at the same time. One always gets sharper than the other, no? Or you buy a seven day set, and you find one or two get beautiful edges but there is only frustration in making the rest catch up to them. Everything about them is the same, save for tiny variations in the grinding process.
I'd love to hear from razor makers on this topic. Am I barking up the right tree (or just barking mad?) How do you try to get the geometry right - eyes, micrometers, jigs?
I expect that different issues come into play at various points in that range. I'd expect that softer vintage Sheffield steel will make a razor easier to hone, and over-hardened HRC66 steel will take a lot longer. And perhaps not just hardness, but toughness and other metallurgical qualities.
Then there are the difficulties caused by odd designs like a massive smile. Geometry comes into it rather obviously for the very difficult to impossible razors. But if we ignore the extremes of material science, design and geometry, we are dealing with 90% of razors that sit somewhere in the middle.
I'm wondering if small errors in geometry - really small - make the differences among most razors? When you grind by eye, there are limits to the tolerances you can achieve. I'm not a razor grinder, but I know what has to be achieved, and it looks something like this:
(Assuming you have hardened and then tempered the blade blank without inducing any warping)
1. Constant width of spine from one shoulder to the shoulder on the other side, and each shoulder must be perfectly flat in plan view.
2. Constant distance from one shoulder of the spine to the edge, and precisely the same constant distance on the other side.
3. A perfectly straight edge, in elevation, is required to allow the above.
4. The edge must be perfectly centered, in plan view, between the shoulders of the spine.
5. Even with all the above true, the razor must have no side to side curve along its length.
That's an awful lot to ask, and it obviously comes down to acceptable tolerances. Let's say you are an experienced razor grinder, and you have ground thousands of razors eight hours a day, five days a week for decades. Nearly all the razors you turn out will be serviceable, but there will be inevitable variation. A few thou here and there that might account for the difference between a razor being easy or hard to hone. Is it the case that only egregiously bad grinding makes a razor incapable of being honed, and that the stones simply remove a little more metal here and there to cover up the sins of the tired grinder?
Think of this - if you buy a pair of razors for a travel set. Same make, model and bought at the same time. One always gets sharper than the other, no? Or you buy a seven day set, and you find one or two get beautiful edges but there is only frustration in making the rest catch up to them. Everything about them is the same, save for tiny variations in the grinding process.
I'd love to hear from razor makers on this topic. Am I barking up the right tree (or just barking mad?) How do you try to get the geometry right - eyes, micrometers, jigs?
