sharp/dull blade drawing Tsunesaburo Blue Steel small map
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Microbevels front and back.
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Copyright (c) 2002-15, Brent Beach

Test Summary

This test is of a current Tsunesaburo Blue Steel laminated blade sold by Japan Woodworker.

This is a 2-3/8" wide blade, which I tested in a Stanley #604-1/2.

The blade is 0.087" thick and came with a 30 degree primary bevel. I reground the bevel to 25 degrees before sharpening.

Pro Reasonably priced blade with very good performance.

Wears like high carbon steel (no chip outs, high quality edge throughout sharp to dull cycle), but almost as durable as most A2 steel blades.

Con Nothing really. The best performer in the group of high carbon steel blades.

13-09-02 One note, from the DICK Fine Tools data sheet for this steel:

Grinding

It is very important to avoid temperatures above 150C once it has been hardened and annealed. Grinding the steel on a dry sharpening machine or belt sander is especially harmful its crystalline structure. We recommend using a water-cooled sharpening machine or sharpening by hand using Japanese waterstones.

So, when grinding stay well back from the edge. Of course, 3M on glass is an excellent alternative for honing.

Update - Feb 2007

I was reviewing the blade test chart and noticed that this blade tested much better than other High Carbon steel (HCS) blades. In fact, it is almost as durable as A2 steel blades. Yet, for some reason, I had ranked it as just a good blade. Perhaps it was because I tested it at the same time as I tested an Academy Saw Works HSS blade.

While not in the same class as the ASW blade, it is certainly superior to all other HCS blades I have tested. As well, because the edge wears without any edge failures, it is probably a better blade than any A2 steel blade I have tested.

A very good blade!!

The Test

March 6-7, 2005.

The blade comes with a 30 degree primary bevel. I ground this back to 25 degrees before honing according to my usual standard: three front and back bevels using 15, 5, and 0.5 micron 3M abrasive paper.

This blade was tested in parallel with a current production Academy Saw Works M2 blade. That is, I sharpened the blades together and tested them together, alternating which blade went first during each set of 50 passes along the 4' Douglas-fir board.

The front bevel, 60 X magnification, as delivered.

The lamination is clear. The hard steel back is called Blue Steel in the catalog.

I don't know how they managed to get such different appearance on the two parts of the blade. The scratches cross the full bevel, but the softer steel portion looks very different. Perhaps they did some kind of heat treatment after grinding this bevel. The appearance when I ground then honed was much more uniform.

front, 60x, lamination
The back, 200 X magnification, as delivered.

The machining marks on the back run parallel to the edge, so does not show up well with this lighting. The back has not been honed at all.

back, 200x
The front bevel, 200 X magnification, after honing.

I labelled the 4 bevels. I now routinely add a scratch on both bevels to allow me to find exactly the same part of the bevel at each stage of the test.

The bevel labelled 120 is the primary bevel - ground using a 120 grit AlO sanding belt.

The 15u (micron) abrasive was getting a little worn. The 15u bevel was not as wide as I usually get, and the 5u abrasive ended up removing almost all of the 15u bevel. The 0.5u abrasive removed almost all the of 5u abrasive scratches.

sharp
The front bevel, 200 X magnification, after 100 passes along 4 foot douglas-fir board.

The wear bevel appears as a faintly darker band along the edge. It shows no glints, a characteristic of what I have been calling High Carbon steel blades (like older Stanley blades, O1 and W1 steel blades). It is 3 to 4 pixels wide.

100 passes
The front bevel, 200 X magnification, after 200 passes.

By enlarging the picture (digitally) I can see that the wear bevel is about 9 pixels wide. This is well above average for this type of steel, almost equal to A2 steel.

200 passes

Steel type and Back Wear Bevels

Since I tested this blade and an M2 steel blade in parallel, the difference in the appearance of the back wear bevels under the microscope was obvious.

The Tsunesaburo Blue Steel blade after 200 passes.

The back wear bevel, the almost black region at the edge, shows no scratches at all. There appear to be no irregularities in the surface that are large enough (roughly 0.7 micron or larger) to reflect light.

The wear process appears to be removing very small pieces of the blade, and is doing it faster than in the M2 steel case, but in a way that leaves a very smooth surface.

200 passes
The Academy Saw Works M2 blade after 200 passes. The back wear bevel shows up as a very bright area - an indication of lots of irregularities off which the light can easily reflect.

The wear process is dislodging relatively large pieces of the blade, but is doing it very slowly.

Unlike A2 blades however, the largest pieces dislodged appears to be quite small - there are no chips along the edge.

200 passes

Bottom Line

The Japan Woodworker - Tsunesaburo Blue Steel blade has durability well beyond other blades in the High Carbon Steel group, almost comparable to A2 steel.

A very good blade at a reasonable price.

LINKS

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