Through dovetails are a great way to join the sides of a case. They're the easiest type of dovetail to cut and a very strong joint. One draw back, however, is that this type of joint doesn't hide the groove made for the case bottom (or top). On drawers this is often solved by using a half-blind dovetail at the front and through dovetails only on the back, where letting the bottom groove show doesn't matter.
Sometimes all corners will be seen, such as on a box lid or as with these desk trays. In these situations I often turn to mitering the half-tail and half-pin at top and bottom. This joint hides any grooves that might be left exposed otherwise. Consider these examples.
Here's how I make them. The layout begins like any other through dovetail joint. I'm a tails-first guy, so I start by adjusting a set of calipers until I find a "step" that works. The goal is to step the calipers from one end and finish with the narrow pin width you want when you reach the other end. No science. Just make a first guess and adjust until you're satisfied. Cut the tails as usual. Nothing different here.
Next, I use each set of tails to mark the corresponding pins. My method is to slide the tail side left and then right by a saw width to mark each. This leaves an easy line to follow when starting the cut. Rob Cosman has a video illustrating this method. I don't mess with tape or a rabbet plane as he mentions. It's easy enough to line these up and then lock the clamp on my Moxon vise. Most of the pin cuts are as usual. However, you only want to cut the inside of the half-pins on either end. Don't cut through. Turn the side around and cut at an angle as you see in the last photo.
You could remove the waste at this point, but I prefer to make the miter cuts next. This involves mitering the half-tails and half-pins at each end of the joint. I clamp a guide block at the corner to set the angle. After the miters are all cut remove the waste and check the fit. If necessary you can fine tune the miters with a sharp chisel.
Sometimes all corners will be seen, such as on a box lid or as with these desk trays. In these situations I often turn to mitering the half-tail and half-pin at top and bottom. This joint hides any grooves that might be left exposed otherwise. Consider these examples.
Here's how I make them. The layout begins like any other through dovetail joint. I'm a tails-first guy, so I start by adjusting a set of calipers until I find a "step" that works. The goal is to step the calipers from one end and finish with the narrow pin width you want when you reach the other end. No science. Just make a first guess and adjust until you're satisfied. Cut the tails as usual. Nothing different here.
Next, I use each set of tails to mark the corresponding pins. My method is to slide the tail side left and then right by a saw width to mark each. This leaves an easy line to follow when starting the cut. Rob Cosman has a video illustrating this method. I don't mess with tape or a rabbet plane as he mentions. It's easy enough to line these up and then lock the clamp on my Moxon vise. Most of the pin cuts are as usual. However, you only want to cut the inside of the half-pins on either end. Don't cut through. Turn the side around and cut at an angle as you see in the last photo.
You could remove the waste at this point, but I prefer to make the miter cuts next. This involves mitering the half-tails and half-pins at each end of the joint. I clamp a guide block at the corner to set the angle. After the miters are all cut remove the waste and check the fit. If necessary you can fine tune the miters with a sharp chisel.
