I have been recently conversing with Don Naples regarding sharpening woodworking tools. As you may know, Don travels the states and the world providing woodworking-related sharpening instruction and demonstrations. He also developed and now promotes and demonstrates the Lap-Sharp sharpening system. However, Don believes that woodworkers need to learn how to sharpen and use sharp tools. In his own words,
I wanted to include this statement because Don realizes the importance of learning how to sharpen tools and what makes a tool sharp. He is not there to simply sell the Lap-Sharp system.
The following are Don's comments regarding the Lap-Sharp system and sharpening in general:
The Lap-Sharp system is the only system that can be used wet or dry (wet is preferred) while providing abrasives from a coarse grind to a 1µ hone on both the back and bevel edge of a tool.
We have had a number of woodworkers review this system, with mixed results. In one case, there was no mention of the slow speed rotation, no mention of wet operation, no knowledge of the purpose of reversible rotation, no mention of how fine a hone can be achieved, etc.
The difficulty in reviewing a sharpening method lies in the fact there are few if any sharpening experts. According to analysis theory, it takes 10,000 hours to become an expert. “Ten thousand hours is equivalent to roughly three hours a day, or 20 hours a week, of practice over 10 years… No one has yet found a case in which true world-class expertise was accomplished in less time. It seems that it takes the brain this long to assimilate all that it needs to know to achieve true mastery.”
The difficulty here is that most of us want to be expert woodworkers [not sharpeners]. I do not know of anyone who wants to spend 10,000 hours sharpening tools. The reason I developed the Lap-Sharp® is so I would not have to spend hours sharpening tools, but rather achieve water stone sharpening quality or better in less time. I did accomplish my goal, as the system uses flat interchangeable aluminum discs that hold the PSA backed abrasives.
These discs do not go out of flat as water stones do, so it is easier to achieve really flat tool backs. If you look at the Japan Woodworker website it shows the use of water stones and has a picture showing a forward and back stroke on the surface of the stone that does not include the edge of the stone. Popular woodworking showed a picture a few years ago that showed the flaw this creates in that the center of the stone is worn, but the edge is not, so the center becomes lower than the edge and the tool is then sharpener with a rounded or dubbed back. If one takes a piece of fine abrasive paper and places it on a flat surface (reference plate) and then takes a single swipe of the tool on the abrasive, you will most often see (at least in my experience) the scratches to not reach the cutting edge. The tool back has been rounded. If it does reach the edge, you are doing well in your sharpening technique.
Your website (http://www.thewoodshop.20m.com/howto_sharpen.htm) lists “Scary Sharp” and one mentions of sharpening to 1200 grit while another mentions 2000 grit. Silicon Carbide used in wet or dry paper, is meant to be used on non-ferrous metals, not steel. It is very friable and breaks down so quickly, you must keep moving to a new area of the abrasive to have this method work, or you will create a polished surface and not be abrading the metal.
Some comment that they get a shinier finish with wet or dry [abrasives] than with water stones. They are correct as the water stones are still working while the Silicon Carbide has turned to a polish powder. If one takes a piece of 600 wet or dry abrasive, and rubs a piece of steel back and forth, you will soon see it begins to shine. Now take a piece of new 800 grit paper and take a single swipe with the same tool. You will see scratches in the polished surface as the new finer abrasive is coarser than the worn 600 grit abrasive. At 1200 grit one achieves a 15.3µ [µ = micron] abrasion, at 2000 grit is 10.3µ, neither is near an 8000 grit water stone which is 1.2µ.
Many woodworkers start working with woods that are relatively simple to surface and plane. These woods we used in shop class typically include Pine, Maple, Oak, Mahogany, Walnut, and Cherry. When a sharp tool is needed to cut these, one learns to achieve a reasonably sharp tool edge. Then we move to figured Maple, Lacewood, Wenge, Jatoba, Bubinga, and more, we find our tools are not sharp enough. If one learns to sharpen to this new level of sharpness, all these woods can be planed. I even plane them across the grain (needed due to the design of the surface I have to flatten) and am able to plane against the grain, required since the grain patterns sometimes do not always have a single direction along an edge. Taking tools to a finer level of sharpness I believe is learned out of necessity as we move to working with more difficult woods.
Some woodworkers show a bald arm and believe they have achieved a satisfactory level of sharpness if they can shave hair off parts of their body. If you can’t do this, the tool IS dull. However, if you can do this, it IS NOT an indication that the tool is sharp. If the tool is dubbed, but reasonably sharp, it will shave hair but may not work well in a plane. If one uses a wet grinder and (I have seen) strops the back of the iron with the stropping wheel, you have just rounded the edge, but may still be able to cut hair, but this tool will not work to its potential in a hand plane.
Swarf [Jack: debris or waste, I call sludge] is another issue. It can become part of the abrading process and cause slight flaws in the abraded surface. I noticed this with grits from 10µ and finer. The Lap-Sharp uses Trizact abrasive to 5µ as this abrasive has an apex structure that allows the swarf to fall into the valleys while the peaks continue to abrade. If you use Microfinishing Film abrasives from 9µ and finer, one can use WD-40 or Formula 409 as a lubricant and be able to wipe the swarf from the abrasive surface. Water and detergent will not work at this fine an abrasive level and this type of abrasive.
We offer a very wide selection of abrasives, to sharpen a wide range of tools. The grinder manufacturers who offer and require many options to work with woodworking tools have an out-the-door price similar to the Lap-Sharp. They are also limited to grinding only bevels as they really are not designed to flatten the backs of tools and are limited to a single grit (I know there are stone graders) stone that is usually 65µ. That abrasive provides an edge far from a finished edge, so one still has to purchase water stones (or use another method) to flatten the tools and hone to a fine edge. This should be added to the cost of the grinder as it is required to finish the sharpening process.
Wood Artistry, L.L.C.
408 Moore Lane
Healdsburg, CA 95448
Tel: (707) 473-0593
Fax: (707) 473-0653