Thursday, November 26, 2009

Carcass dovetails...

    I found a few hours in the past couple of days to finish the carcass dovetails. I've been using common techniques with mixed results in the past and have picked up a few tips from poking around the net. I even came up with something on my own. Probably not new but I've not seen it yet.
    Laying out dovetails in walnut can be difficult for me because it's hard to see a pencil line or a knife line. I tried a white charcoal pencil but the line wasn't fine enough for me. I had an idea to use masking tape which I think was a good idea. Here's what I did. I laid the tape down where my marking line would be, then I marked my line with a marking gauge cutting the tape. I removed the tape to reveal a nice distinct reference line. Have any of you used tape for layout lines before?

     It is much easier to follow a line when you can see it. I finally got around to using a spotlight and I was glad I did. I do need to pick up a florescent bulb some time because the regular ones get quite hot when they're 12-inches away!

     It seems almost unnecessary to mark the waste portions but it really reminds you which side of the line you need to be on. Definitely a few seconds well spent.

     Cutting out the waste with the coping saw has been my least favorite part. These dovetails are about an inch thick so cutting between pins with a 5-inch blade hasn't been fun to me. I'm hoping the dovetails for the drawers will be easier by comparison. I'm thinking about trying out a fret saw like that Cosman guy.

     Chopping out the waste with chisels can be a pretty tedious job but I kinda like it. It tends to be a repetitive, rhythmic task best done while listening to good music. I've started to use a chopping guide for this part to help me keep the lines straight. Before I always seemed to have at least a couple stray chops which ruined what was otherwise decent dovetails. I picked this up from The Village Carpenter, Kari Hultman who picked it up from David Finck. The face of the block that guides the chisel is beveled a couple degrees so that the chisel cuts a slight hollow toward the middle of the board's thickness. This prevents leaving humps in the middle which results in gaps after assembly. I use a smaller chisel first to get rid of most of the waste, chopping down about half-way. To me this is easier than a broad chisel at this point.

     When I chop away all but 1/32 of an inch I switch to a broad chisel and take a clean finish cut. After one side is done I turn it all over and finish the other side. By the way, holdfasts are great. The ones from Gramercy at  seem to be the standard anymore, and for good reason.

     I'm still not quite there with dovetails but I am getting better and much more confident. There's always a lot of talk about hand-cut dovetails; they are the Holy Grail of joinery. It seems many woodworkers are constantly searching for tricks or tips or magic spells for success. In my short experience I have found a few tips which have helped but the one thing which has helped me the most and which virtually guarantees success in the future is PRACTICE. Just like the time when I tried to break-in my new dovetail saw by cutting a couple hundred kerfs in scrap. Not only did I break-in my saw, I got better at sawing. You can't make or buy a jig for practice.

      I finally did glue up the carcass. It was rather... stressful. Even though I was convinced I had everything adjusted to go together, it was a pain in the butt to pull everything together. I ended-up using clamps, a mallet and a lot of cussing to coax it all into place. Even though it was a tight fit I ended up with a few visible gaps. Fortunately, that's nothing a few small wedges and glue can't hide.
     I'm really looking forward to the next round of joinery, hand-cut housed dovetails. This will be used to join the drawer dividers to the carcass sides. I've been trying different techniques to cut this by hand and I think I've got a process that will work for me. Unfortunately there's not a lot about this hand-cut joint on the net. Maybe we can change that. Check back in the next week or two and I'll have something to show you.

Happy Thanksgiving!