Hand Tools

WD40 smudge

david weaver
Noticed in the picture that the tsune iron looks a little different than the other two.

That's just tiny particles of WD 40.

It's interesting that any oil or anything at all on an iron will show up on the scope as a huge amount. This is the amount of WD40 on an iron after it's been wiped off with a rag or jeans, etc. I'm guessing that it's still there because that's the amount that's left on your jeans after you wipe oil off of the iron. Not a groundbreaking thought, but interesting that when we think about wiping oil off, we're really sharing it between iron and rag, and whatever is on the rag and iron will go back and forth.

the other two irons that are clean are double wiped off...once on jeans or rag, and then again on tshirt before taking microscope picture.

The tsunesaburo iron is clearly harder by a mile vs. the other two. Diamonds don't really care about anything except they do penetrate slightly less deep in harder steel (natural stones certainly do this, making the finest edge on low carbide steel when the hardness is approaching the max a stone can handle).

Even with 1 micron diamonds, the edge is exceptionally fine and whether or not the penetration is slightly less deep on one iron vs. another is meaningless. I think the reality of an edge like this is that chasing finer with honing films and other things meant really for pigments (and some have been adapted to razors) is really pointless, especially if it either adds steps or increases the chance that an edge is unfinished.

I used to use diamonds eons ago and used a 0.25 or 0.5 micron powder. I have (in theory, if I could find them) those in vials still, as well as 0.1 micron. Discretion in actually working wood over the years tends toward making sure the edge is finished without too many steps vs. trying to get edges finer than that in these pictures.

Since the pictures are not three dimensional, what we're actually looking for when we take a picture like this is no three dimensional aspect to the edge where it disappears, and that the disappearance is nearly a straight line, or as close as possible. Scratches that terminate away from the edge are relatively meaningless. The tiny scratches right at the edge are probably from the bias of pressure there (they are the 1 micron diamond scratches) as well as some spring back from a honing substrate.

Still, this is a very "precious" feeling method. You have to keep everything clean, and i can understand why people using it would chase an iron that promises long edge holding vs. one that's easy to refresh. That fact probably won't be conveyed in simple wear tests.

It'll be interesting to see surface quality as these irons wear, though. I suspect the blue steel iron will wear a little faster, but leave a better surface and stop cutting reasonably at a higher level of wear.

I don't think brent beach took irons to the point that they were no longer producing an acceptable result (can't remember), but I am going to do that.

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