Mrs. Woodworker knows nothing about woodworking. Mrs. Woodworker knows everything about woodworking.
The other day, I was agonizing (ah, the trials of being a craftsman) whether to go with the 6mm wide, 40 mm long tenons (those “plugs” on the bandsaw in the picture which help join two pieces of wood together) or the 5mm wide, 30 mm long tenons for some kitchen cabinets I was building (see our post about making cabinet panels if you’d like to make some). In general, you want to use a tenon that’s about a third the thickness of the material you are drilling into. In this case, the material was 3/4 inch, or 19mm, which means a 6mm tenon would be about right, but the tenons would be a bit long for certain mortises (the holes the tenons go into) and go all the way through the face frame of the cabinet if I wasn’t careful. I could have offset the mortises by cutting 15mm into one piece and 25mm into the other side, but that would require great care to make sure I didn’t accidentally punch a mortise all the way through by having the depth setting wrong on the mortising machine (Festool Domino). Given that the cabinet had 38 tenons, that was 38 opportunities to make a mistake. Sometimes failing is good, but not when you are at the end of a long project like this.
In trying times like those, it’s sometimes wise to consult a higher power: Mrs. Woodworker (substitute The Husband, woodworking mentor, etc. depending on your particular situation). Mrs. Woodworker would tell you she knows absolutely nothing about woodworking, but her advice has proven to be remarkably prescient over the years. In this case, I asked her advice and her eyes quickly glazed over when I said “mortises” and “tenons.” When I was done speaking, and she said “remember the other day when you quit for the day because you said you were getting tired and stupid and didn’t want to make any mistakes? Shouldn’t you find a simple approach in this case, so you don’t accidentally make a mistake?” Brilliant! The answer was clearly to cut down the 6mm tenons from 40mm to 30mm, to idiot-proof the process and prevent mortise cut-through.
Lesson learned: Do what your spouse/significant other/partner tells you.