What is S3S?
The abbreviation “S3S” is a description of surface finish, usually pertaining to hardwood species. It stands for “Surfaced Three Sides”, which, as used in Goosebay’s hardwood lumber descriptions, indicates that two faces have been planed, and one edge has been processed with a straight-line rip saw, rendering the edge straight and smooth. The other edge is left rough, as the board came from the sawmill.
This finish allows woodworkers who don’t have access to a joiner to size their lumber with a table saw by placing the ripped edge along the fence of the saw.