Fixing Mistakes: How to Replace a Broken Dovetail Pin
In woodworking, you cannot avoid mistakes. Let’s face it: No matter how skilled we become, we still slip with a chisel now and then or get too aggressive with the tablesaw. Occasionally, despite our best efforts, a router bit chips away a corner.
Sometimes it’s simple enough to grab a fresh piece from the lumber rack and start again.
But if you’re working with a limited supply of lumber, don’t want to discard a grain-matched board, or already have invested hours in shaping or carving a part, a joinery mistake poses a serious dilemma.
Fortunately, you almost always can save the part you’re working on. Here’s how to fix a broken dovetail pin.
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Salvage with a shim?
If you find that you’ve pared a pin at an angle, you can repair the mistake with a shim.
Glue a piece of small, thin stock to the side of the pin, then trim it flush to the inside face of the board and to the end. Pare the restored pin carefully with a chisel for a tight fit.
Replace a pin
It’s also possible to salvage a pin that you’ve broken off or weakened by paring it too small.
To do this, I begin by chiseling away the broken pin altogether.
Mark out for pin removal. Scribe lines to create a rectangular mortise matching the maximum width of the pin.
Continuing with the chisel, I then cut an open-ended mortise immediately behind the pin location.
Chisel a socket. Remove material by making angled chisel cuts to create a ramp to the baseline at the front of the pin. Then pare from the front until the bottom is square.
This mortise will accept an oversize, rectangular replacement piece from which I’ll cut a new pin.
Use cutoff stock for the repair. Fit and glue in the rectangular repair piece.
Cut a new pin. Trim the new piece flush with a saw and handplane. Use the tail board to mark out the sides of the new pin. Be more careful this time!
Excerpt from Seven Joinery Fixes from FWW #186
Photos: Steve Scott