I've seen woodworkers go to great lengths to ensure their dovetails are evenly spaced out, the Alan Peters method using callipers works very well. However I've always eyeballed my marking out as small differences in dovetail spacing are not picked up by the eye.
What I do find immediately noticeable is a variation in the width of the pins. I've been toying with the idea of making a double kerf starter which would make identical sets of kerfs to place the saw blade in, but then I remembered I had kept all my used Japanese saw blades over the last 20 years. So with two of these blades, a piece of thin veneer and some double sided tape, I made my own double bladed kerfing saw.
Run up against a square (or using my 90 degree magnetic guide) the test results were impressive, giving perfect pairs of cuts from which the tails could be cut. The technique would be equally well suited for cutting dovetails freehand or with one of my magnetic guides.
This spacing is suitable for finer dovetails leaving an overall gap (with the waste removed) of just 1.75 mm. This was achieved using two 372 saw blades with a 0.6 mm thick veneer stuck in-between.
Whilst I was at it, I made up a thicker version with an overall 2.5 mm spacing for larger carcass dovetails.
Very nice. I have to wait another 20 years to build up the extra blades though.
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