Fixing Dovetail Gaps (Repairing my Foolish Mistake)

So here it is. This is the result of my completely avoidable mistake. Actually, this side isn’t even the worst one. I’m a little too embarrassed to show the really bad corner. At any rate, this joint does not fit together tight enough to hold without being fixed. Sometimes you can get away with a slightly loose joint when using hide glue, especially if only one of the tails is loose but the others are good. However, in this case, the entire joint is bad. It would fall out on it’s own if not repaired. The good news is that the fix is really easy, and almost invisible when it’s done, so there’s no need to scrap the entire thing and start over. Instead, we look at these situations not as mistakes, but opportunities to practice skills we would otherwise not have the opportunity work on. That’s my story, and I’m sticking to it :).


I begin making the repair by making a really long wedge. I want something with almost no taper when it’s cut to size. The last thing I want to do is drive in a fast tapering wedge and split the drawer side. Then I’d have no choice but to make a new piece. Instead, I take a stick from the cutoff bin and plane a long taper into it. I clamp one end to the bench (you can just barely see the clamp bar below the bench at the bottom right in this picture) and plane a long taper into it by planing right off the end of the bench. I want something that basically feathers at the end. Using the same species helps to hide the repair. If you can use a cutoff from the same board used to make the part you are repairing, the color and grain pattern will match even better, further hiding the repair when you’re done.


The resulting wedge looks something like the picture below.


The end is very fragile but I’ll cut it off gradually as I fit the wedge to the gap. I cut a length off of the stick about 1-1/2″ long using a chisel. I then make the wedge the width of the tail with the same chisel. I begin fitting the wedge by cutting a clean edge on the wedge with the chisel. I try the fit in the gap and if it is too loose, I pare the end back. I want the fit so that I can push the wedge in with finger pressure and it closes the gap completely. Be careful here as a wedge that fits too tightly can easily split the pin board. You should be able to insert and remove the wedge without any help from a mallet. The glue will make the fit tighter later so don’t make it too tight now.


Fit all of the wedges dry before you begin gluing anything in place. Once you start gluing, you can’t make any adjustments. Make sure everything fits snug but not too tight and then label every joint and it’s respective wedge so you can be sure to put the wedges back in exactly the same spot and orientation when the glue goes on. You need to work relatively quickly. This is where the slow setting time of liquid hide glue really shines. The slow set time gives you plenty of time to glue and assemble the entire drawer before inserting any wedges. You may need to tap the wedges in once the glue is on but do so gently. You don’t want to snap a wedge off below the surface once it has glue on it.


Once the glue has dried, carefully pare the wedges down to the surface with a really sharp chisel. There’s still a chance of breaking them off below the joint surface so take it slow. Once the wedges are pared low enough, you can switch to a plane and clean up the joint surface as you normally would a joint that didn’t need repair. The wedges are readily visible in the final joint as it’s very difficult to match the end grain perfectly to make them disappear. Really, I’m probably the only one that will ever notice them, but they will serve as a constant reminder of my mistake and hopefully prevent me from making it again.