Join Date: Sep 2008
Location: Chattanooga, Tennessee
Even though we try to choose straight, un-warped, untwisted, unchecked blemish free lumber, sometimes the lumber isn’t milled correctly or can come from different setups and can be different dimensions or have un-noticed defects. Some lumber may be milled too thick, but seldom too thin, some may be straight ripped one edge.
At a lumber supplier you may see the materials referred to as S1S, S2S, S3S or S4S. S1S means the materials have been surfaced 1 side which usually means one edge has been straight ripped.
S2S usually means the materials have been surfaced both sides but not straight ripped either edge.
S3S means the materials have been straight ripped one edge and both sides surfaced.
S4S means all surfaces have been milled.
Sometimes while milling, an unadjusted/untuned machine can cause irregularities which must be addressed in order to have blemish free materials. Looking along both the width and the length of boards, flipping them over to inspect both sides is necessary to observe defects; even the most trained eye can overlook some defects.
Most big box stores will have lumber dressed to finish thickness, whereas a lumber supplier will usually leave the lumber at least 1/6 inch or so thicker, so any scars from transporting/handling can be removed while thickness planing.
It is advisable to leave the materials at the full thickness until ready to use as materials can move during storage. It is also advisable to store your materials in a way so while they acclimate to the humidity and temperature, that they don’t warp, twist, bow or check. One word of caution, remove all or as much dust as possible from materials to be planed, as dust can and will dull your blades quickly.
There is no such thing as perfect materials. That is the reason we have machines to mill our materials as close to perfect as possible.