Handplanes and Dovetails

When most people think about cutting dovetails, they think: handsaws. However, there’s more to dovetailing than sawing. You also need to be mindful of your handplanes when you’re dovetailing. They can create gaps or help prevent them.

This week I’m dovetailing a bunch of drawers and smallish boxes, so my planes are heavy on my mind.

If I remove any material from the inside of this pin board, the joint will become gap-tacular.

First, let’s talk about how handplanes can cause gaps. If you cut your pins and tails for your box and then plane all the inside surfaces, then you are asking for trouble. Planing the inside surfaces of your pin boards will make you look like a crap-tacular sawyer.

Don’t get it? Think about it for a minute: The interior surface of your pin board contains the wide triangles that fit into your tail board. Every stroke of your handplane on the interior of your pin board makes the joint looser and looser by removing the widest part of the joint (the same advice holds true for the belt-sander crowd).

You can, however, plane the interior surfaces of your tail boards with little consequence. The more planing you do, the more trimming you will have to do after assembly, but this is really no big deal.

So how do you avoid this problem? Plane the interiors of all your surfaces before you cut your joinery. This is a good idea for many reasons. First, planing helps remove any twist or bow in your stock, which makes joinery easier. And second, it prevents your joints from getting looser as you refine their surfaces.

For casework, here’s how I do it: First, I dress all the long-grain surfaces with a jointer plane. Then I cut the joinery. Assemble the carcase. Trim the proud nubs. Smooth plane the exterior. Be done with it.

When cutting a cross-grain rabbet, first draw the tool backwards so the nicker can define the shoulder. This results in cleaner cuts (and is historically accurate, thank you Peter Nicholson).

Here’s the completed rabbet. It’s less than 1/32″ and a bit more than 1/64″. It’s all you need.

Now that we know that handplanes have an evil side, how can we use them to tighten our dovetails? Use a moving fillister plane to cut a shallow rabbet on the inside of each tail board.

This shallow rabbet is the width of your stock’s thickness (use a 3/4″-wide rabbet for 3/4″-thick stock). And the rabbet is less than 1/32″ deep. What does this rabbet do? It makes transferring your marks from your tail board to your pin board (or vice-versa) much easier. The mating board nests right into the rabbet so you don’t have to fuss around with lining things up on the baseline.

Glen D. Huey showed me this trick in 2002. He was using it to line up pieces of differing thicknesses, but the rabbet also made transferring the marks from one board to another almost foolproof.

I use a moving fillister plane to cut the shallow rabbets. A true moving fillister has a depth stop and fence to regulate the depth and width of the cut , plus it has a nicker that scores the cross grain ahead of the cut. This reduces tearing.

This shallow rabbet, which is used by other dovetailers such as Rob Cosman, is completely worth the effort to make it. It takes just a few strokes with your plane and prevents an endless cycle of fussing and adjusting.

The Veritas Skew Rabbet Plane meets all the criteria to make this cut, as does the Philly Planes moving fillister plane and vintage moving fillisters. The Lie-Nielsen Skew Block Plane (with nicker) is lacking only a depth stop (you have to count the shavings and be careful if you use it for this purpose).

Next week: How a hammer can tighten up your dovetails.

– Christopher Schwarz

Here I’m pushing the rabbet against my pin board. This makes transferring the shape of the tails a can’t miss affair.

Editor’s note: Want to learn more – lots more – about using handplanes? Read Christopher Scwharz’s book “Handplane Essentials.”