Sharpening Stones

SHARPENING STONES

SOME THOUGHTS ON STONES

The hand sharpening stone is often taken somewhat for granted: usually the only consideration it is given is to avoid dropping it, and to keep it oiled or moist (water stones) and free of sawdust. However, as with any fine tool, a little attention occasionally will provide optimum results. We offer a few tips on the lowly handstone: First, of course, is to keep it clean. Wiping with a rag will remove most surface gunk, but doesn't help particles that are clogged inside the pores of the stone. One way to rid the stone of these is to flood the surface with a good thin oil and then "bake" them out in strong sunlight or under a strong lamp. The offending particles are driven to the surface where they may be wiped off. This may be repeated as necessary until the stone looks almost new.

Most craftspersons are familiar with dressing power grinding wheels, which removes the outer worn abrasive particles and provides new, sharp particles for faster cutting with less heating. Not so familiar is a similar process for resurfacing handstones; this produces not only faster cutting but also a flatter surface for those plane and chisel blades that you want to be really flat.As you may know, even a slight amount of hollow (.002"-.003") makes it difficult to hone the back edge of your blade. The technique is quite simple and involves lapping the stone on an abrasive surface. The stone manufacturers lap the stones on a slowly rotating cast iron plate with an abrasive and water slurry.

For those of us lacking slowly rotating cast-iron plates, the abrasive can be wet-or-dry silicon carbide sandpaper (lubricated with water) or it can be silicon carbide grit sprinkled on a flat piece of plate glass or cast iron. (Silicon carbide is available in powder form from most abrasives distributors, as is carborundum powder which is often used for lapping Japanese water stones.) When using silicon carbide grit, I have found that water or oil just adheres the grit to the stone, and you end up grinding more glass than stone. I haven't tried it yet using a cast iron plate. For sandpaper, you'll need to use several sheets: 120-150 grit is about right, but you might want to experiment with various grits, depending on the fineness of your stone.

Give it a try, I think you'll be pleased with the results.

Roger Sherron

JAPANESE WATER STONES

In our first catalog we carried a full line of sharpening stones from coarse India to hard black Arkansas. Since being introduced to the merits of Japanese water stones and after having used them for several years now, we have come to feel that the water stones offer just about everything the full line of India and Arkansas stones offered, and at a fraction of the price. In general, the Japanese water stones give a sharper edge much faster, and without the mess of honing oil.

We were first impressed with the efficacy of the Japanese water stones when visiting Brian Burns of Palo Alto. His set-up involved three water stones. When they were not in use they were kept in water to which a dash of detergent was added. In no more than five minutes he went from a dull low angle block plane blade to one with such a keen edge that we watched in amazement as he took a long thin shaving of a hard maple board riddled with birds-eyes. During the course of the sharpening he had used all three stones from a coarse to a finish - not an expensive finish stone either -to achieve the edge.

Water stones tend to wear faster than other man made stones and natural stones simply because they were made to do so. As the stone wears it exposes new particles with sharp cutting edges which quickly offer up a keen edge on your blade. (It takes just about half the time to get an edge on a blade with a water stone as it does with an India or Arkansas.) To compensate for this sacrifice of long wear, our water stones are large and can be used for years with proper care. (Of course your stone will require resurfacing from time to time to keep them flat. See Roger's notes on the lowly handstone.)

The Japanese water stones we carry are Aqua brand, we are told, a jump up from the King stones we use to carry.

Text From The Luthiers' Mercantile Catalog - 1993