14 April, 2009
Hand cut dovetails
I spend a lot of free time on woodworking projects of all sorts. I find it relaxing (most of the time) and it's a great way to de-stress after a rough day of fixing trucks. Last summer I started to do more work with hand tools and it has been quite a learning process. I've been concentrating on getting better at cutting dovetails and, for the most part, I'm improving. Slowly. If you go to YouTube and watch videos of a pro cutting dovetails or read about it in a woodworking magazine, it seems to be a very simple process. It is an easy process, but the execution is much more difficult. You'd think that something as simple as sawing to a line wouldn't be very difficult but it is. Another thing that can make dovetails frustrating is not knowing what a sharp tool is. Cutting dovetails with hand tools involves many different skills, and those skills don't come without some practice. For example, the previously mentioned sawing to a line. I thought it would be a simple matter of buying a backsaw, marking a line and then following it. As I found out, there's a lot to learn. It took a lot of practice to finally see that I consistently deviate from the line in one particular way. After more practice I learned how to prevent that deviation. I'm still not great at sawing, but I'm a lot better than I was a year ago. Oh, the saw itself plays a key role. I've found that a Japanese style pull saw (without a back) works well for me versus a traditional western style back saw. There's one style of western saw I've yet to try, but money is short and a new saw isn't in the cards at the moment. In the photo (it's a tailboard) you'll see the tails marked out. The shaded areas are the waste which needs to be removed. I use the pull saw to make the vertical cuts and then use a coping saw to make the horizontal cuts. If you are like me, you would probably mark a line and saw right down that line. That method doesn't make for nice fitting dovetails. The vertical cuts are made on the waste side of the lines and the horizontal cuts are done in a similar fashion, but I leave a little more waste. After the waste piece is cut free, I use a chisel to pare the wood down to the horizontal line (it's called a base line I believe.) Chiseling, there's another skill that didn't come naturally. The biggest problem with chiseling is having a properly sharpened tool. When I bought my first hand plane (a Record smoothing plane) and first set of chisels, I had no way to sharpen them. Hell, I thought they came out of the box ready to go. They don't, trust me. A trip to the "Big Orange Box" for a sharpening stone and I thought I had it made. Nope, not yet. After digging through the stacks of old woodworking magazines, I learned that the back of a chisel needs to be flattened before working on the bevel. The same goes for plane irons. After a few hours flattening chisels and plane irons, my arms felt like Jell-O and my fingers were raw. But, I had flat tools. Next it was on to the bevel. I used the side sharpening method on the bevels because it was easier for me to hold the tool in the proper way. Two hours later I had what I thought were some razor sharp chisels. Any professional woodworker would have declared them dull. I didn't know it at the time, but the cheap sharpening stone I bought (the only one I could find locally) was pretty shitty. I also had a hard time keeping the chisels in position while sharpening them. Mail order to the rescue! I bought a honing guide which eliminated my problems with holding the chisels, but I still had a crappy stone. The chisels were sharper than before, but not much. Last weekend I finally decided to give the "Scary Sharp" method a try and wish I would've done it years ago. It is nothing more than putting various grits of sandpaper onto a reliably flat surface (i.e. plate glass, marble, granite etc.) with spray adhesive. You start with the coarse grit and then work your way through the grits in succession until you reach the final one (2000 grit in my case). The combination of the honing guide, flat glass and the many grits of sanpaper yielded a mirror surface on the first chisel I sharpened. I gave that first chisel the age-old test of trying shave some hair off my arm. Shave it did, and cleanly at that. My plane has also been a joy to use. Right now, all of the skills I've been working on are beginning to come together and are yielding better work. I put the dovetailed box together the other day and it looks very good (for me that is) with only a couple of really bad gaps. Those gaps are because I cut on the wrong side of the line on a pin board. Stupid mistake, but I learned from it. I'm looking forward to getting the box glued together and using my razor sharp plane to trim the joints flush. That will have to wait. I got sick of my workbench racking and squeaking so I disassembled it (I didn't build it) and decided to renovate it with mortise and tenon joinery. I plan on building a new bench in the near future, but reworking my old "squeaker" is turning out to be a good learning experience. But, that's a whole other story.