I'm building a small (12"D x 24"W) workbench for doing woodwork in my apartment. I want to dovetail the legs to the top, but the tail on the end will be about 1/2" wide on the narrower end. Is this acceptable, given that the tail will be about 1-3/4" deep (thickness of the top)? Will it be too weak?
That joint looks strong enough to me.
The bigger problem, though, is that you will have wood movement issues. The top will get bigger and smaller seasonally (in the front-to-back direction) while the board you're joining to it will not. This is because the grain in the top is running perpendicular to the other board.
I would suggest redesigning this as a sliding dovetail or a pinned mortise and tenon with enlarged pin holes on the tenon (like a breadboard).
(This is assuming that the board on the end is oriented in the normal fashion. If it has the end grain on the top then there would be no problem with movement.)
Side note: Are you going to incorporate the tail vice into your design? I think that's a cool bit of whimsy.
You say you want to dovetail the legs into the top, but I interpret your drawing showing what appears to be the vice pad, not legs. I'm sure I'm missing something. Can you post a couple of different views of that end - actually, both ends, if you wouldn't mind?
I was going to argue with @Dukesilver on wood movement, but if you are going to run the grain on that end wood perpendicular to the top, as opposed to in line with it (like a drawer box), then I have to agree that serious caution is in order.
I agree on strength, (if everything is oriented correctly) although I would add a center tail. The extra mechanical forces are necessary to hold that expanse of end-grain-to-face-grain together.
