I'm wondering whether S4S (Surfaced 4 Sides) is absolutely necessary for all my woodworking projects. Typically, I prep boards by jointing one face, then the edge, planing for another flat face, and finally ripping a square edge on the table saw. While I get that S4S boards are typically easier to work with, I'm curious if it's overkill for certain projects. For instance, if I'm building a table with legs and skirts, can I get away with just ensuring the inside faces are flat and square, without needing the outside faces to be perfectly flat? I'm looking to improve my skills in light timber framing, using larger stock like 4x6's and 6x6's with mortise and tenon joinery. Traditional layout methods don't always expect S4S, so can I work effectively without it? Also, I don't currently have a jointer or planer but am considering getting a jointer first, as I believe it's more critical for achieving square edges than having two parallel flat faces. Would love your insights!
3 Answers
Back in the day, the focus was on getting one face and edge flat, while the rest could stay rough as long as it was functional. Just a heads-up: a 6" jointer might struggle with heavier pieces like a 10' 6x6. A lot of effort goes into prepping larger beams, and achieving square edges on those can be tricky!
You might not need the whole face to be perfectly flat; just the area where you're doing the joinery. If you're using hand tools, a bit of roughness is totally fine, especially for hidden parts. It's all about how you cut your joints and what looks good. For something like a timber-framed pergola, you might only need the joints to be flat for aesthetics. So if your joints are square and flat, you're in good shape!
Traditionally, hand tool techniques only require one flat face and one straight edge, which makes it possible to reference everything else. Inner faces often stay rough-sawn, which is practical. Sure, for some projects like piston-fit drawers, you need things to be precise, but for simpler structures like table bases, one accurate edge works just fine... as long as you're disciplined with your layout!