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Sharpening Chisels and Plane Blades

The Crazy World of Sharpening

Nowadays if you search woodwork magazines or the net on the subject of sharpening chisels and plane irons you will be presented with a bewildering array of complicated solutions to this apparent problem.
There is a craze for sharpening, more or less separate from the needs of woodworkers. A great deal of merchandise is being sold on the back of it.

It can't always have been this way. Excellent woodwork was done in the past, but in older books the only sharpening kit regarded as essential was the oil stone. The grindwheel was useful if you had access to one - but not essential.

No doubt some woodworkers still see it that way, but many, especially newcomers and amateurs, are struggling with complicated sharpening systems. These always involve jigs and/or a lot of other kit. If you google sharpening chisels and look at a few pages you soon get the idea.

Can we get back to basics? Why should we? How should it be done ?

I have found a way that suits me and which I think must be how it was always done, as follows.

Freehand "Rounded Bevel" Sharpening

Why should you sharpen freehand?

How is it different from the complicated systems?

How is it done?

The minimum kit needed is a double-sided oil stone, an oil can and a few rags. This is ALL you really need but the process can be refined with a few extra items.

Start on the fine side of the stone, well charged with oil at all times.

1. An edge in good order which just needs a bit of honing

A chisel or plane blade is worked energetically up and down on the oiled stone, being held so that as near as possible it doesn't exceed the desired honing angle, usually 30 degrees. It is essential that the handle is dipped as you go, so that the honing angle is reduced during each stroke.
Even more essential is that the angle must not be lifted above 30 degrees. This is the hardest part for a beginner but it becomes quite easy with practice, and in any case does not need to be exact - a few degrees out won't make much difference.

The dipping produces the rounded bevel and can be done vigorously with as much force as you can muster, which makes the process quicker than carefully trying for a flat bevel.

To even-out wear and get a straighter edge it is necessary to try to use the whole area of the stone and also change direction and angle across the stone.

If not too blunt a wire edge will come up quickly which you can feel if you slide a finger over the edge, off the face i.e. avoid a cutting action!
When you can feel (or see) a wire edge or burr along the whole of the edge then you turn the chisel flat on to its face and take off the wire edge by rubbing the chisel around (in a circular motion) - keeping the face firmly held flat on the stone.
This may turn the wire edge back to the bevel side in which case you hone again but gently so that the new wire edge is taken off or turned back to the face side.

If you want a very sharp edge you repeat the two steps: hone the bevel and flatten the face, several times - but taking less time and using less pressure with each step, so that you are turning/removing a finer wire edge each time until it falls away or is easily removed by light stropping.

If a wire edge doesn't come up promptly in a few seconds you have:

2. An edge in less than good order which needs a bit more than just honing

You need to back-off more of the bevel on the coarse (faster) stone so you repeat the process exactly as above but at a shallower maximum angle, usually 25 degrees, dipping as above, to produce a rounded bevel but without necessarily reaching the edge.

Then move back to the finer stone and try again for the wire edge as above.

You may have to repeat these steps several times if the chisel was badly out of shape or very blunt.

3. An edge damaged or in very poor condition

You could grind this back as in 2 above, if necessary going right to the edge or past it to remove chips and nicks. This will be slow so you may need to resort to the power grindstone. A water-bath stone is best as this will avoid the risk of overheating the metal.

However you do it you need a ground edge bevel about 20/25 degrees - either the tangent at the edge if you have a rounded bevel - or overall if you have a hollow ground bevel.

What you have now is effectively:

4. A new tool

The way to deal this is to go back to 1 above. It should only take a few seconds to get a good sharp edge.

Complicated systems emphasise flattening and polishing the face of a new tool. If flattening really is necessary then you should return it to the shop if you can. Polishing too is unnecessary unless you are doing a lot of paring cuts where friction from machine marks might be an issue. This can be remedied in seconds by the application of candle wax, instead of hours of polishing
A little less than perfectly flat/polished is OK in woodworking terms and in any case will gradually disappear over time as the tool is re-sharpened.
Ignore any advice which talks of thousandths of an inch or hundredths of a millimetre.

If machine marks or rust pits are so bad that they interfere with the ability to hone a good edge, then you might have to polish the tool, or scrap it.
The occasional nick in the cutting edge can usually be lived with if the alternative is hours of polishing, and will eventually be removed by subsequent honing.

The best way to flatten and polish faces is to use the tool a lot.

ROUNDED BEVEL

This idea is the first obstacle for most people in that virtually every article on sharpening condemns rounded bevels as totally unnacceptable.
This is because a rounded bevel is usually the result of careless sharpening where the honing angle has been raised in order to bring up a wire edge sooner. If this is done too often the cutting angle increases too much and the chisel or plane blade has to be re-ground.
The rounded bevel I'm talking about is quite different - the edge has the same angles within it as a conventionally honed/ground edge i.e. 30/25 degrees - but the transition between them is rounded off so that the bevels are not flat, but the cutting edge still stays at 30 degrees.
It doesn't matter what shape the rest of the bevel is (within reason), flat, rounded, or hollow ground but if you do it by hand rounded is easier and quicker.