One point that should be clarified is that there is a significant difference between the Japanese Waterstones that you buy from say Lee Valley for around $25 - $50 (depends on grit) and natural Japanese Waterstones which can cost ~$1000, so a full set could run you ~$10 000. The quality also varies significantly and it is far from trivial to pick out the good ones. Most traditional Japanese woodworkers tend to prefer the natural waterstones, one possible reason being they have a very "soft" action which is well suited to the *very* hard and thin blades they tend to use.
Now I am not making the argument that traditional methods on natural waterstones are "better" than modern power equipment with various abrasives. But there are significant differences; the initial cost of the equipment, the training required, and the time it takes to sharpen a blade using it. In general you can expect to pay much more for something done by traditional methods than a "replica" by current methods, even if the current methods give an equal or even better performing product. That being said, the prices seem reasonable to me, just in regards to the traditional aspect.
To clarify the comment I made in regards to slicing, to me, slicing means cutting with a vastly reduced amount of force in comparision to push cutting the same material. To be specific, as an example, the Buck/Strider folder I had with a shaving polish would push cut 3/8" hemp rope with about 100 - 110 lbs of force. If I lowered the finish to 600 grit (DMT rod), I could drop the force to around 35 lbs and cut the rope in 2-3 slices. If I kept the finish high and tried to slice the rope, I would need pretty much the same level of force as on the push cut and that would be basically what I was doing as since the teeth are so small the amount of material they shear through on the draw is not significant and thus it not really slicing.
Now various steels act slightly different in this regard, there are some that will retain much more of a "bite" at higher polishes than others, but even they are no match in regards to slicing at a high polish as compared to themselves at a lower grit. I am not talking about small changes like 10% either, but much larger effects like several hundred percent. There is nothing complicated about this, you are just comparing basically the action of a saw which requires low vertical force to an axe which requires a lot.
Jerry :
<font face="Verdana, Arial" size="2">I'm often surprised by the comments on repeated sharpening on these forums. If it's done right it doesn't need to be done often.</font>
Blades tend to have to be sharpened every day if you want to keep them near optimal performance, assuming they are used of course. As an example, Busse Combat has posted various performance specs for the INFI line, one of which is something like 24 pieces of 2x4 before the blade loses razor sharpeness. This isn't a large amount of wood if you are burning it. When I take the BM out to cut up enough wood for a couple of days I will go through several times that amount. I am also not cutting up clean lumber, but through bark which will contain dirt and such that will obviously blunt a blade much faster . It is not just chopping either. If I am breaking down cardboard boxes at work, they will be dirty and again dull a blade fairly quickly. Same thing for most uses, a large number of tests quote say 100+ cuts on hemp rope, well yes if it is new store bought rope, try the same thing on used cord.
<font face="Verdana, Arial" size="2">Polished surfaces are more wear resistant than rough surfaces. </font>
The wear resistance of a steel has little to do with the edge retention in most cases as regards to immediate blunting as it is caused by deformation and/or fracture. The only time it is really significant is if you are willing to work with the knife at much less than 100% performance. The main benefit of greater wear resistance is to basically increase the time that you can get between honing by allowing the use of maintance techniques which align the edge such as steeling and as well reduce the amount of honing you have to do when you do need to fully sharpen the blade as it loses very little metal in use. There are exceptions to this, but you have to be cutting very abrasive material which is capable of wearing a significant amount of material off of a high alloy steel in a short amount of time, like used carpet for example.
In regards to the wear resistance of rough vs polished surfaces, yes a polished surface does wear better, however you have to remove a significant amount of material off of the rough surface when you polish it. If you subtract this out of the material lost in the wear testing, then they are not nearly as different. For example, as an easy to picture case, take a two files, now polish the teeth off of one. Now use both files on say concrete. You will note that yes the teeth will wear down much quicker on the NIB file than the flat surface will abrade on the one you polished, but the NIB one has to have the teeth all worn away before it even starts to wear on the same surface that the polished one is wearing on right from the start.
Anyway all that being said, polished edges do resist fracture and deformation much better than coarse ground ones for the same reason that a plain edge blade is more durable in regards to twisting, impacts and hard cuts than a serrated edge. For these reasons, high polished edges will readily outlast coarse ones on harder work like chopping. They will also readily outcut them in push cuts (require much less force), but will be themselves outperformed greatly in slicing vs coarse ground edges.
-Cliff
[This message has been edited by Cliff Stamp (edited 03-07-2001).]
