Solid lumber

materials:
  - id: post_stock
    from: lumber.hardwood.s4s
    species: walnut
    thickness: 75
    width: 75

Every size on this page is actual, not nominal. These are what the board measures when a merchant hands it over, which is the only size worth designing to. A thickness that is not on the list is RES-009, and the finding names the nearest two that are — a 35 mm rail is a rail you cannot buy, and finding that out at the timber yard is worse than finding it out here.

lumber.hardwood.s4s

Hardwood, surfaced four sides.

Species	walnut white_oak red_oak ash maple cherry beech birch poplar
Thicknesses	19 · 25 · 32 · 38 · 50 · 63 · 75 mm
Widths	50 · 63 · 75 · 100 · 125 · 150 · 175 · 190 · 215 · 240 · 290 mm
Lengths	1800 · 2100 · 2400 · 3000 · 3600 mm
Rough allowance	length 50 · width 6 · thickness 3 mm
Cost	≈ 4200 per m³

Boards above about 240 mm wide are increasingly hard to find in one piece and usually mean a glue-up. The width check warns rather than errors — it is a procurement problem, not a design error.

lumber.softwood.s4s

Softwood, planed all round.

Species	pine spruce douglas_fir western_red_cedar larch
Thicknesses	18 · 20 · 25 · 32 · 38 · 45 · 50 · 63 · 75 mm
Widths	40 · 45 · 70 · 95 · 120 · 145 · 170 · 195 · 220 · 245 mm
Lengths	2400 · 3000 · 3600 · 4200 · 4800 mm
Rough allowance	length 50 · width 5 · thickness 2 mm
Cost	≈ 900 per m³

These are planed sizes. The sawn size the board is sold under is larger and is not modelled — a “2 × 4” is 45 × 95 here, because that is what you can measure.

lumber.hardwood.rough

Hardwood, rough sawn. Same species as the surfaced family.

Thicknesses	25 · 32 · 38 · 50 · 63 · 75 · 100 mm
Widths	100 · 125 · 150 · 175 · 200 · 225 · 250 · 300 mm
Lengths	1800 · 2100 · 2400 · 3000 · 3600 mm
Rough allowance	length 75 · width 10 · thickness 6 mm
Cost	≈ 3100 per m³

Sold rough, so the stated thickness is what you start with, not what you finish at. The allowances are correspondingly larger — 6 mm on thickness, against 3 mm for surfaced stock, because a rough board has to be flattened before it is anything.

Use this family when you are milling your own. Otherwise use lumber.hardwood.s4s.

Rough allowances and the cut list

The allowance is the extra on each dimension the cut list asks for, so there is enough board to trim both ends square, joint an edge and flatten a face that has moved.

A part with a finished blank of 2032 × 190 × 38 in lumber.hardwood.s4s appears on the cut list as 2082 × 196 × 41 rough. That is what you buy; the blank is what you cut to.

Sheet goods carry much smaller allowances — 10 mm on length and width, nothing on thickness — because a sheet arrives flat and stays flat.

Choosing a size

Two habits worth having.

Drive the width from the stock, not the other way round.

blank:
  length: deck_length
  width: rail_stock.width          # the full width of the board
  thickness: rail_stock.thickness

A rail that uses the full 190 mm of a 190 mm board wastes nothing and does not need ripping.

Check the length against the available ones. A 2400 mm part cut from a 2400 mm board leaves no allowance for trimming. The next length up is the one you want, and the cut list’s rough length will tell you which that is.