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From Tree to Table · Part 3

Hardwood Thickness, Quarters, and Milling Terms

Short answer: Commercial hardwood is sold by rough quarter thickness, then milled as needed. Trees don’t grow to Home Depot sizes — you buy volume, often as random length and width.

The quarter system

Thickness is named in quarters of an inch of rough stock:

  • 4/4 — 1" rough → about 13/16" or 3/4" finished
  • 5/4 — 1.25" rough → about 1" finished
  • 6/4 — 1.5" rough → about 1.25" finished
  • 8/4 — 2" rough → about 1.75" finished

RL & RW

Random length and random width maximize yield from the tree. You’re buying board footage, not a fixed S4S stick.

Milling designations

  • Rough sawn — off the mill; fuzzy and uneven; you joint and plane.
  • Skip planed (hit or miss) — reveals grain for grading; does not flatten the board.
  • S2S — both faces surfaced to thickness; not necessarily flat (bow/twist springs back). Face-joint it.
  • SLR1E — one edge jointed/ripped straight for the table saw fence.
  • S4S — faces and edges done; typically sold by the linear foot like big-box stock.

Class note: bring or photograph a mill / bundle label and decode it together — photo asset still needed for this page.

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