A Treatise on Sharpening
The basic concepts of sharpening are far less abstract than people realize. When these are understood, the need for jigs and gadgets immediately disappears. Of course, a good result can be achieved with many of these fixtures. The trouble is that just as good, if not a better result, can be achieved in a fraction of the time using a traditional approach. The basic tenant of the traditional approach is consistency, rather than accuracy. It is commonly taught that plane blades and chisels should be ground to 25 degrees and then honed at 30 degrees. The point which is often missed is that being exactly at these angles is not critical. It is critical to remain at exactly the same angle once you start honing. Allowing the honing angle to change during sharpening rounds the edge and ruins the result. So, the first thing to remember is, that while 25 degrees is a good angle at which to grind most plane blades and chisels, and 30 degrees is a good angle at which to hone, it is more critical that the honing angle be exactly maintained, even if that angle deviates by a few degrees. It should be noted that 25 degrees is too shallow an angle for mortising chisels. These should be ground to approximately 35 degrees.
The obvious question that arises is, "how do you keep the honing angle exact?" Actually, it is not as hard as it looks. Assuming that you are starting with an edge that is ready to be honed, hold the blade so that the bevel is flat on the sharpening stone. Now tip the blade up ever so slightly onto its edge. Now go back to having the bevel flat. Do this a few times to get a feel for where the bevel is, and the honing angle. The honing angle is simply a consistent angle a few degrees more than the bevel. You could also sharpen the blade simply by staying at the bevel angle. This is not done because is would require too much metal to be removed, and thus would be too slow. So the honing angle is a few degrees off of the bevel in order to concentrate the sharpening action on the edge of the blade. When the honed edge widens to the point that re-honing has become to slow, then it is time to grind the bevel again, or when the edge has been chipped or damaged too badly to hone out.
The sharpening motion used is also important to keeping the bevel angle consistent. Basically, the more you move, the more likely you are to change the angle and round the cutting edge. A small circular motion is ideal for honing an edge. Running the blade up and down the stone is not necessary, or even desirable. Early cabinetmaker's stones were often round, made from a single rock cut in half. Generally, the smaller the sweep you make, the better the result. Just don't do it in the same place every time or you will develop uneven wear on your stones.
The next issue is what grit to use. Most early cabinetmaker's only had one or two stones at most, and would not even understand the confusion causes by our plethora of choices. In fact, for most work a fine India stone is perfect, with a Hard Arkansas stone being needed only when the finest edge is required. With water stones, a 1000/4000 combination is about equivalent. The only reason to use a coarser stone would be if you don't have access to a grinder. Our preferred solution is the Norton Multi-Oil stone with a Hard Arkansas, fine India, and medium Crystolon stones. It can be argued that water stones cut more aggressively, but they also wear out more quickly. The Norton multi-stone keeps the stones wet but eliminates the usual mess of dealing with wet stones. Importantly for woodworkers, a bit of oil residue left on a fine tool is beneficial, but a bit of water left from a water stone will quickly rust and pit a high-carbon tool steel blade.