Ken Casser
04-09-2009, 9:43 AM
I've been practicing cutting dovetails on my bandsaw per Lonnie Bird's book, and have had terrific results as far as fit and appearance, but my pins always seemed to come out narrower than I had planned. I SEARCHED SMC to see if anyone else was having this issue, but no luck. So, I drew out a diagram of what I wanted to produce and wrote a formula for determining the width of the spacers needed, and the distance the blade needs to be from the fence, taking into account the width of the kerf, etc. Using those formulae, I took a piece of 1/4" poplar, 2 3/4" wide and cut three tails into it, and bang, they came out right on - evenly spaced, pins the right width, etc. I thought, "Gee, I'm a genius. This is great. I have to share this system with everyone." Then I reviewed my formula vs the Book and guess what - his simple means of determining the width of the spacers is exactly correct, and mirrored my results. The thing that I did differently, is that instead of lining up the spacers and setting the fence as shown in the book where the edge of the outside spacer touches the side of the blade, I moved the fence 1/16" closer to the blade - which is the width of the kerf. That simple shift made all the difference. Now, when making spacers, I'll use Mr. Bird's simple method of taking the board width minus the desired pin width, divided by the number of tails. Then rip one long spacer to that dimension, cut it evenly into the number of tails desired, take one spacer and trim off 1/16", then set the fence using those spacers per the book's diagram. Then, remove the narrower spacer and start cutting. I can rest now.:D:D
Hope this helps someone. For Through-Dovetails, I like this method much more than doing it with a router, and the result is a tight fit and a great look. And, you don't have to make all the tails equally spaced, you can vary things to suit your taste, and make any angle you want.
Hope this helps someone. For Through-Dovetails, I like this method much more than doing it with a router, and the result is a tight fit and a great look. And, you don't have to make all the tails equally spaced, you can vary things to suit your taste, and make any angle you want.