I’ve mentioned a couple times that my main source of cheap pine is off-cuts from tongue-and-groove pine siding. I’m running a bit low, but I’ve managed to make a three-foot tall stack of 36″ to 48″ long boards last for most of a year. While the material is fluffy and easy to work, it isn’t exactly stable, and most of the time, is significantly twisted and cupped (thankfully, not often bowed). This presents an obvious problem: final board thickness.
Before preparation, any given piece is only about 11/16″ thick, and the “raw” board can have almost 1/8″ of cup/twist or more. This means that after flattening and straightening to S2S, I’m often a barely a shade over 1/2″ on some parts of the board. Passing the piece goes through the thicknesser takes it down to a hair over 1/2″ all around at S4S.
This is why I’ve gotten in the habit of only S3S’ing these boards when the project can allow for it. For example, the bottom shelf of the toy workbench was made of four such boards. The underside of that shelf will never be visible, so I left the extra mass in the boards by only S3S’ing them.
I also use this trick when I need an inside tenon shoulder or when a board is too wide for my thicknesser, in each case where the inside face will otherwise be concealable.
This trick isn’t available in some applications, however. For instance, I can’t attach drawer runners to the twisted inside face of a side rail (like for the angled leg side table) and the underside of a tabletop should be trued to mate well to the table frame. I guess you could technically use rabbets to solve each problem, but that seems like even more work than just thicknessing properly.
I haven’t disassembled much antique furniture, but I find it difficult to believe I’m the first person to cut this corner when possible. I think this shortcut thing is becoming a running theme.