Spacing Dovetails with Dividers – a Little History
I’ve always been intrigued about the history of the way some English-trained woodworkers set out their dovetail joints using dividers.
I first learned to use this method – which I love – from Rob Cosman. He learned it from legendary craftsman Alan Peters. But where did Peters learn it from?
I don’t know, so I’m always on the lookout for early sources that cite this method.
This week I’ve been consuming “The Practical Woodworker,” which was edited by Bernard E. Jones. No, not the stinky piece of junk sold by Ten Speed Press. I’m talking about the original four-volume set from Waverly Book Co. in London.
It’s a sizable compendium of writings from a long list of experts that was edited into 1,500 pages of information on (mostly) hand-tool woodworking and published in the 1920s (well, that’s when my edition was published).
On page 227 is this great description of laying out pins-first dovetails.
While an expert worker will find the “sockets first” system most expeditious, it is perhaps not the best for the beginner, who will usually meet with less difficulty and fewer mishaps by adopting the “pins first” method, at any rate until some dexterity has been gained.
Here the boards are planed up and shot true at the ends, as before, and are gauged with a shoulder line all round at a distance equal to the thickness of the material. Next, on the shoulder line and at the outer side of the wood measure off at each end half the thickness of of the thinnest side of the pin. With the compasses or dividers divide the intervening space between these marks into as many parts, plus one, as there are to be whole pins (see Fig. 15), and on each side of these divisions mark off half the thickness of the pin, as shown.
Any slight inaccuracy at this stage will affect the appearance but not the fit of the dovetails.
This method is slightly different than Peter’s method. But they share the same fundamental idea: Step off your dovetails with dividers. The Jones method marks off the centerlines of the joint; Peter’s method marks off the extents.
So this 1920s method is close, but not exactly what I’m looking for.
— Christopher Schwarz
Want to learn more about this method?
Rob Cosman covers it in his DVD “Hand-cut Dovetails 2.0.” You also can learn more about it by watching the DVD “The Alan Peters Approach.” Both are available through ShopWoodworking.com.