Hand Tools Archive

A simple point about the pictures..

david weaver
Bill reminded me of this, I may have said it in pieces. You can't really trust the light levels and wear on the face of the iron when the differences are subtle. This is a $425 indian microscope with chinese software (that cost includes the base and camera). It's really good for the price, but it's not an SEM.

What I rely on (I bought this scope to judge natural stones and to examine edges of razors that I sell, though I don't do that regularly now) is the actual picture at the very edge. If the edge is uniform, especially at this level, you can generally conclude that it's well sharpened. After some wear, if it remains uniform, you can generally conclude that it is wearing in very small bits, and will be thin. The more uniform, the thinner the edge will be where it meets wood.

You can see wear on an iron like this with the naked eye, even though it doesn't show up in the second picture. It could be that the wear is removing the tiny scratches from the initial sharpening, or it could be that the focal length isn't the same in the two pictures. But the uniformity of the edge itself (where it disappears into black) is what we're looking for.

Despite the fact that the edge looks shiny freshly sharpened and then less so in the second picture, you cannot see reflection of light when it's freshly sharpened (a good ancillary thing to check when sharpening) and even with 200 feet of maple planed, you can see just a tiny bit of light reflected back at you if you look at the very edge. In the same way, you can look at a straight razor and see if it's been stropped with bare leather because you can only just see the tiniest amount of reflection from the edge.

So, though the curiosity about the features reflected back makes for interesting guessing, it's only the very edge that we're concerned about until or unless a much more prominent pattern of wear emerges (and for planing quality, even then, we're still concerned about the edge).

We've got a long way to go with wear, though. When the iron is sharpened well and the wood is clear, last time with the A2 irons, I'd say I got at least 1000 feet of good planing out of an LN iron, and then another 700 to 800 feet of struggling to try to get the iron to stop cutting (it never really did, but the quality of the wood surface really got horrid as i continued to force on). That was also on hard maple. I didn't use the cap iron back then, so I'm interested to see if the number of feet planed improves with these irons with the cap set.

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