Timber Terms
The WL West Timber Terms Guide
The woodworking world and timber industry have an entire codex of vocabulary and technical terms that aren’t always self-explanatory. This glossary aims to help you understand the timber terms in common use. If you’re not sure about a specific word on our website, feel free to contact us for more information.
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1st
|
First Quality |
| 1/2 | Is a mix of first and second-quality timber. This can contain sapwood, sound knots, cross grain, or natural discolouration/streaking. |
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1/S/E
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One square edge, one waney edge |
| 1+2 White | This term is used for the general description of Maple: white on one side, with slight discolouration on the reverse. |
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5-Axis CNC
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A machine to router, drill, saw, machine in the X, Y, Z, A and B tool rotation. A C Axis would be used for lathe work. |
| A/D | Air drying from fresh sawn to below FSP (Fibre Saturation Point) |
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Air Checks
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Surface cracks small and along the grain – surface in tension |
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Architrave
|
A main beam resting across the tops of columns |
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AD
|
Air-dried |
| Billet Sawn | Growth ring 45-90° to board face. Heart-split. |
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BM
|
Board Measure |
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Bow
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When the centre of a board is raised higher than the ends when laying on a flat surface |
| Boule | French term for a Through & Through log, used in UK timber trade |
| Brown Oak | European Oak (Quercus Robur) with fistulina fungus |
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Butt-jointed
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When two pieces of material are joined by simply placing their ends or side by side for gluing |
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Case Hardening
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Tension-set/ Compression-set |
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Cats Paw
|
Epicormic growths (shoots growing from a previously dormant bud on the trunk or a limb of a tree). |
| C Grading | Coniferous Grading C16>C27 for strength. |
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CITES
|
Convention of International Trade of Endangered Species |
| Cladding | A building’s outer layer of either horizontal or vertical material meant to improve insulation and weather resistance |
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CND
|
Colour No Defect |
| Cross Cut | Cutting to dead length |
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CTS
|
Cut to Size (to the nominal sizes required). |
| Cupping | A board in tension on one face |
| D Grading | Deciduous Grading D20>D70 for strength |
| Dead Knots | Evidence of ingrown bark – unstable |
| DM | Decimetre – square area of a board |
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Durability
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A measure of durability of how long and untreated sample of a timber species will last before decay |
| FAS | First & Seconds (clean one face) |
| Fissure | A drying crack usually along long pith/heart in dying |
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Gate Parts
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HURR – The main vertical of the gate from which the gate hangs
HEAD – The second vertical
BACK – Top rail of the gate
SPLEATS – The remaining cross rails
BRACE – Strengthening rail built diagonally across the gate. SINGLE~CROSS(2 braces)~DIAMOND
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GIB
|
Grown in Britain |
| Grain | A term often misused – relating to all the axial elements running parallel to the edge of the board |
| FIN | Finish size |
| FE | Feather Edged |
| FS | Fresh Sawn |
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FSC
|
Forest Stewardship Council |
| FOM | Free on motor. This term indicates the status of a product loaded safely onto the customer’s vehicle, but deemed ex-yard (ie: no longer on-site). |
| FSP | Fibre Saturation Point. When a tree is first felled, it is considered to be in the green state, and contains a very large amount of moisture. This moisture exists in two different forms: as free water that is contained as liquid in the pores or vessels of the wood itself, and as bound water that is trapped within the cell walls. It is only once all the free water has been lost that the wood will reach what is called the fibre saturation point, or simply FSP. |
| H/G Timber | Homegrown timber – not imported. |
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Half a Knats
|
50% of a Knats (see Knats) |
| Half-lapped | Where two pieces of stock, typically of the same thickness, have half of the material removed so that the two boards fit together with no added thickness at the joint. |
| Heartwood | Inner rings inside the sapwood band |
| Heart Shake | A crack in the heartwood near the centre of the tree usually due to shrinkage through seasoning or old age |
| Hoppus | A measurement for logs or round timber to calculate the volume, or a tapered cylinder if temperate, or cylinder if tropical. |
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KD
|
Kiln-dried |
| Knats | A very small measure (northern term). |
| Live Knots | Absence of ingrown bark – stable |
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M/C |
Moisture Content |
| Merchantable | Can include knots and face checks, but constructionally sound |
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NHLA
|
North American Hardwood Lumber Association |
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NOM
|
Nominal size |
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Oak Grading
|
For beams see BS5756 |
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P/2/S
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This refers to the board being planed on two faces |
| PAR | Planed on all four faces (from the nominal sizes) |
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PEFC
|
Programme for the Endorsement of Forest Certification |
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PTG
|
Planed, Tongue and Groove |
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PTGV
|
Planed, Tongue and Groove and 'V' |
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Proforma
|
Payment prior to order being actioned |
| Quarter Boards/Quarter Sawn | These boards are radially cut which expose the medullary rays. It is rare for sawmillers to cut logs using this method, as it increases both waste and cost to mill, making the overall price increase substantially. |
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Ring Shake
|
Separation of one annual growth ring from another |
| Sapwood | The outer rings of the log, this can be very visible in some species eg: Oak and Yew, but almost visibly non-existent in others e.g.: Ash and Sycamore |
| Scotia | A concave moulding, especially at the base of a column |
| SE | Square Edges |
| Smidgeon | Another small measuring unit, similar to Knats above (southern term) |
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1SE
|
One square edge, one waney edge |
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Spp |
Timber Species |
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Spring |
Board laid flat but curved |
| Star Shake | Excessive cross-sectional drying in logs |
| STM | A term where the timber selector selects timber to cover the customer’s timber cutting list. |
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Tangential Boards
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These are boards produced from the outside of the log |
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Texture
|
Fine grain > coarse grain |
| Tongue and Groove | When boards are joined by means of interlocking ridges and hollows down their sides |
| T/T | Through and Through – A log sawmilled into plank and left with the bark edges on it |
| Twist | Propeller shaped board |
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Waney/Bevelled
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The sloped-off shape on the end of sawed timber (instead of square) |
| Weather-board | A form of external cladding designed to overlap (unlike flush cladding). Particularly effective in damp or maritime climates where there is a risk from high salt-content spray. This can have a 1/S/E or square edge, usually fresh sawn if external cladding. |
| WE | Waney Edged – as T/T above |
| WRC | Western Red Cedar |