For the past month or so I’ve been experimenting with sharpening, not just chisels and plane irons, but also saws, scrapers, and profiled tools. I’ve been pretty successful thus far, but that is a relative term because I am only comparing the sharpness of my tools against the sharpness of my other tools. Still, it doesn’t take a degree in ancient woodworking to figure out if your tools are sharp or not.
Often, when touching up an edge, a woodworker will describe having “honed” the tool. If you look up the word ‘hone’ in the dictionary it will likely say, ‘to sharpen’. But in the world of woodworking, sharpening and honing are often thought of as two separate entities. ‘Honing’ may be considered maintaining the edge of a tool that is already sharp, and ‘sharpening’ may be considered the transition from a dull edge to one that cuts. I guess I can live with those descriptions, even if to the rest of the world the words are interchangeable.
Anyway, my little experiment is nothing ground breaking, but here’s how it broke down. I used the six main bench chisels, the iron of my jack plane, and the iron of my smooth plane as the control group. Let’s also consider that these tools were already set-up and have obviously been sharpened in the past. Basically, I “honed” each tool on only an 8000 grit water stone followed by a leather strop charged with honing compound. So? Well, my experiment was basically alternating the number of strokes. I started off taking 10 strokes on the water stone, and 20 on the strop. I would use the tool, and then come back to it the following day. As I said, nothing ground breaking, but I did find out something interesting.
I found that with a tool that was already close to sharp, no more than 15 strokes on the water stone were ever needed, however, I could easily take 30 or more passes on the leather strop, starting off with a heavy hand and taking progressively easier swipes and that would dramatically increase the level of sharpness. In fact, it seemed that when I took too many strokes (‘too many’ being a relative term) on the water stone it actually did more harm than good. Long story short, as soon as I felt even the hint of a burr I went right to the leather.
On a tool that hadn’t been maintained as often, such as my jointer plane iron, I found that starting with the 1000 grit stones, 15-25 passes, followed by 15 (or so) passes on the 8000 grit stone, followed by the leather strop were easily enough to get the iron back to a high level of sharpness. In all instances the leather strop made all the difference. Why?
I don’t read up enough on sharpening to know the scientific answer, but my guess is that polishing your edges with a strop and buffing compound removes the slight imperfections on the bevel of your tools. As these imperfections are removed sharpening becomes progressively easier. This may sound like common sense, because it is, but the strop is key to this. In my experience, sharpening on an oil stone, or a diamond plate will give you a nice edge, but it generally seems to take the same amount of time to re-hone that edge with each sharpening. However, as I’ve continued to sharpen using the strop as the final step, I’ve found that I could raise a burr with as few as 8 strokes.
To sort of confirm this little theory of mine, the one bench chisel I have that has never been stropped, my 3/8 chisel, took between 25 and 35 passes on the 8000 water stone to raise a burr. After several honings and dovetail joints, I used the leather strop, approximately 40 passes, used the tool again, and re-honed, and I had raised a burr with under 15 passes.
So what does my little experiment prove? Maybe nothing. There was nothing really scientific going on here. I’m not Leonard Hoffstadter. But in my garage I’ve found that despite what some people tell you, a highly polished edge seems to sharpen much better than one that is not polished, as well ground as it may seem. I’ve also found that since I began using a leather strop in earnest my tools have been far sharper and are consistently easier to sharpen.
So my conclusion is: if you don’t use a leather strop to sharpen then get off your ass and get one. For less than twenty dollars you can pick up a block of wood, a piece of leather, and some honing compound. Do it and I can pretty much guarantee that your tools will not only be sharper, they will be easier to sharpen.