Monday, 25 March 2013


Should I write a post on sharpening? dangerous ground. There is more written about this than almost anything else in woodwork, and with good reason. Without sharp tools good woodwork is impossible and certainly un-enjoyable, possibly unsafe, not to mention taking longer if it is a production situation.

The problem is the vast volumes written tend to focus on details of method rather than the result, often with the intention of selling the particular equipment, which is usually expensive. If you end up with a sharp chisel it matters not how you got there.

I do not intend to criticise any of the options out there as I am unqualified to do so, not having used them extensively. I can only report on my own experience over 50 years.

The other issue is skill. As with any hand operation a skill is usually involved. This may vary from simple operation of a semi automatic machine to complex procedures which will improve with practice; another reason why short term reviews have limited value.

My own opinions have changed and developed over the years to a point where sharpening is not a big issue for me. I sharpen tools when they need it and it takes only a few minutes.

Like many people I started off with a combination carborundum stone and some oil. I found it difficult to maintain a consistent angle either on the bevel or across the end and it was so slow.

The first upgrade came with a simple Eclipse roller type guide, which improved some aspects but did nothing to speed up what was a tedious operation, and often avoided for too long, with consequent problems on the bench. I did find that thinning the honing oil with parafin helped keep the stone clear. I had not discovered the benefits of dressing the stone and discounted old men's tales of rubbing on a paving slab as unconvincing.

Along the way I acquired a dry grinder and spent even more time honing to try to get behind the blued edges I had ground. Even "high tech" white wheels did not fully resolve the problem.

My next upgrade was a Tormek wet grinder with leather buffing wheel and I still use this for accurate initial preparation of cutting edges. With no danger of overheating the edge and the motor doing the work there are worse ways to spend five minutes. The recent upgrade of the straight guide to locate on the flat side of the chisel is a great improvement on the old one, which highlighted errors in the tool making, especially on bevel chisels, producing an angled edge as a result. Cambered plane irons are produced either by leaning on alternate sides as you grind, for small cambers, to use of the flat support table for more aggressive shapes. I do not use it for the backs of tools, which I tend to let polish over repeated honings rather than a major and very tedious flattening operation when they are new. In any case many chisels have slightly hollow backs which allows only the edge to require preparation.

I use the leather buffing or stropping wheel (pre-soaked in thin oil and charged with honing compound) only for polishing where required, and not for actually honing an edge, as I fear rounding over from pressure on the resilient surface. This may be unfounded in skilled hands, and I have watched some very convincing demonstrations, but I prepare my edges other ways.

My final sharpening method uses waterstones from 1000-8000 grit with frequent use of a Nagura stone to clear debris from the stone, remove small high spots and work up an abrasive slurry. Many woodworkers dislike the "mess" from waterstones but I find the speed of cutting makes up for this and a dedicated area near a sink is all that is needed.

Stone preparation is equally simple. Scribble a wavy line, covering all the surface of the stone, with a soft pencil and rub on some 100 grade wet and dry silcone paper on a piece of plate glass. This need not be huge, about 400mm x 300mm is sufficient, and in my case is an old cupboard shelf. I have heard that the heat treatment of toughened glass can distort the surface however have never found this to be the case in practice so put a straight edge on it and take a look before consigning you finest blades to it. I use enough water to keep the stone moving freely, do not let it become sticky and rinse regularly. I tend to use a full sheet of wet and dry and offer the stone diagonally. Try to use the flat of the hand on the stone to put even pressure accross the full surface. The stone will not bend but it is easy to favour one end which means you will end up with a tapered stone. When all the wavy line is gone then the stone is flat!

I hone chisels and small tools by hand, maybe with a visible angle guide such as a wedge of MDF, at the appropriate angle. More often I register from the ground edge then "tip it up a bit" and hone at that. I use the Veritas system for plane irons where the precise angle is more important. The crowned roller helps maintain the honing angle with cambered blades, a important function missing from many guides, and the skew guide is good if you need one.

The Veritas system is good, comprehensive, long lasting but expensive: it suits me.

As far as angles are concerned I hone most tools to 30 degrees on a 25 degree grind. The exceptions are low and high angle planes, honed at 27 and 45 degrees respectively and English paring chisels (which will not be hit with a mallet) at 27deg. Japanese laminated chisels should be honed at a single angle of 30 degrees to minimise the tendency of the brittle edge to chip.

My view on steels is that A2 is fine for high angle work, where it's extra resistance to abrasive wear prolongs the edge, but it should not be honed below 30-32 degrees or chipping can occur. What is worse is that this seems to vary between manufacturers. For lower angles A1 or other oil or water quenched carbon steel is better at resisting chipping but will  not hold the edge as long as A2. There are ever more exotic choices available but a great deal of top class work has been done with A1 and A2 and the average woodworker needs no more.

The actual honing process is quite straightforward. Starting with the 1000 stone I make the smallest honed edge possible to remove all the grinding marks. I then progress to a 6000 stone to remove the marks from the 1000 grade and then a final polish on an 8000. You can see the difference between stones as the dull grey appearance becomes ever more polished. In all cases I use the Nagura frequently and flush the whole thing with plenty of water. I recently acquired a second hand Veritas stone pond which I like, unlike (obviously) the previous owner.

In the case of the 1000 stone I expect to be able to feel a slight burr on the back when I have honed right to the edge. This is best removed on  the 6000 stone so as not to coarsen the back of the tool or damage the surface of the final 8000 polishing stone, which can happen. I finish with a stropping action against my jeans or the palm of my hand to take off any remaing burr and find this is fine for all normal planes and bench chisels. I'll leave you to decide on the Health and Safety implications of either!

For carving tools and hand gouges it may be beneficial to do some additional stropping on a leather pad (mounted on a piece of MDF), charged with some lapping compound, jewellers rouge or car polish such as Solvol Autosol. In some cases MDF itself can act as a useful strop surface and discs can be turned for use in a drill or lathe for gouge honing.

Well there you have it. Not rocket science but, if followed regularly with tools not left to get too dull, will provide offer a quick, effective and, to some, even pleasureable way of getting the best from your woodworking edge tools.

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