Wednesday, January 21, 2009
Sharpening with Scary Sharp
Sharpening tools is a critical skill. Dull tools don't function properly (or at all) and lead to frustration. Being frustrated is not fun. Woodworking should be fun. So, learning to sharpen is paramount.
There are a lot of methods or systems out there - water stones, oil stones, motorized platters etc. Find a system that works for you. I got lucky and found the Scary Sharp system just as I got into hand tool work. It works great!
What is Scary Sharp? Well, basically it is sandpaper on glass. That's it.*
The first key is that the abrasive paper has to be glued FLAT to the glass (which of course also has to be flat). I do this with a thin coat of spray adhesive (nasty stuff - use outside). I have heard that some people just use water to temporarily stick the paper to the glass - I don't trust that idea, but of course, I could be wrong. If the paper is not flat, you will round over your edge, defeating the whole point of sharpening.
Another key is to progress through multiple grades of abrasive paper. The more grades, the less time on each grade to remove the scratches from the previous grade, and the whole process goes smoothly. Done right, Scary Sharp is not slow. It takes me less than a minute to refresh an edge. A couple of minutes if I need to redo a full bevel.
In an effort to eliminate any excuses to postpone sharpening, I made a dedicated sharpening station. This takes up precious shop space, but is very convenient, allowing me to sharpen whenever I want with no set up. I walk over to the sharpening bench, sharpen, and get back to work with a sharp tool.
On the top is the Scary Sharp system. Four glass plates with abrasive paper attached. Left to right the plates have 180/220, 300/400, 500/600 and 1000/1500/2000/2500 grits respectively. The other sides of the plates have coarser grits for heavier work, but I don't use them nearly as much.
On the shelf underneath are various other sharpening related materials: saw vises, hand grinders, various honing guides (The Veritas Mark II is great, but shortly after getting it, I decided to make the leap to honing by hand - much, much simpler!), my Granfor Bruks axe stone (I use it on my drawknives - love it!), large black markers, a box of small strips of abrasive paper for sharpening curved irons, and various dowels and small pieces of wood to be use with the strips of sandpaper. And my Norton Water stones live down here too. I got these a couple of years ago when I though maybe there might be something better than sandpaper. I mean, a lot of people swear by them, so I thought I would give them a try. Yikes! Awful! What a mess, and I couldn't even come close to what I could do with Scary Sharp. I gave them a couple of days, and then packed them up. I'm either going to sell them on Ebay or break them up to make slips for the carving chisels I don't own yet. I'm sure I could get them to work eventually, but why bother? I'm just glad these weren't my first experience with sharpening when I started years ago!
A brief example of the system in use.
Here's a plow plane iron from Ebay. First I want to check to the back for flatness. Using a black marker, I coat the last inch or so.
After about five strokes on the 220 - the thin black line at the edge shows a clear back bevel on the iron. Not what I was looking for. Now I have more work to flattening the back before working on the bevel. It's time to flip the plates over to the coarse sides.
After about four more minutes on the lower grits - that's more like it. Now I can flip them back over and work my way up the higher grits.
One minute total on the fine stuff and it's a mirror! Now it's time for the bevel.
Since I am not shaping the whole bevel, I only care about the very edge. The paper cuts fast, and it's easy to overdo it. Only a few strokes each grit and it has a tiny polished bevel. Combined with the flat, polished back, that equals a very sharp edge. Scary Sharp in fact!
And a final shot of the iron at work in the plow. The shavings are still on the rough side, since there is no chip breaker and no real mouth on this plane. So the result of having this iron truly sharp is not a matter of leaving a fine finish like it would be in a smoothing plane, but I can sure feel the difference in the effort it takes to plow the groove.
Total time spent was about 7-8 minutes, and most of that was flattening the back which I will never need to do again. What's more, the sheets of abrasive paper are getting old and will need to be replaced soon. Then it really works fast!
I know the Scary Sharp system is not for everyone, but it works great for me. If you are just getting started, give it a try. It's inexpensive and easy. Or if your current system is not making you happy, give Scary Sharp a shot.
*If you Google "Scary Sharp" you will find a lot of information, but one of the best places to start is here: http://www.woodbutcher.net/scary.shtml Rod Peterson is a galoot who has posted a duplicate of the now defunct original "Scary Sharp" page and also has information on the origins of the technique. Thanks Rod!