In trying to incorporate more hand tools into my projects, I am finding the 3/4-inch-thick mortise and tenon joints on my current garden bench project a little challenging—specifically, gaps where the shoulders meet.
If I were using a Festool Domino and miter saw, it would be fairly easy to cut everything in advance, exactly to length, and get joints where the shoulders meet to all seat properly without gaps. But doing it with marking knives and gauges, chisels and hand saws, even with what looked like properly scribed lines, each joint ends up slightly off, and each joint has slightly different issues (this problem solving and attempt to develop hand skills is part of the fun, of course, and exactly what led me in this direction).
I have been working in pairs, i.e., cutting the tenons and mortises at each end of the front rail, test fitting and trying to get as close as possible, then moving on to the rear rail, then the top rail. But I haven’t been striving for perfection on any particular joint until I am ready to do the final dry fit and can see where the problem areas are. I am wondering if there is a preferable approach in terms of work flow and efficiency. Might it have been better to start by cutting all of the mortises on the project, and then trying to get a perfect fit on each tenon and shoulder before moving onto the next joint. Right now, I am at the point where it looks like a bench, but if I want to refine a particular joint, I am having to disassemble most of the bench.
One other question. Someone mentioned undercutting the rear of the shoulders. Does this refer to undercutting the rear side of the joint itself so that any gap would not be visible from the front or sides of the piece of furniture, or instead, chiseling slightly deeper toward the tenon so that the perimeter of the shoulders seats better on all sides.