The Woodworker & Woodturner – September 2019

A-Z of timber terms & jargon TECHNICAL

http://www.getwoodworking.com September 2019 The Woodworker & Good Woodworking 43

Timber frame extension

These test pieces show varying degrees of

case hardening

Timber frame joint – detail

Wood drying

Traditional casement window

Photograph courtesy of Honiton Joinery

Cascamite powdered
resin wood glue

Carpentry joints
Carpentry joints can be described simply
as constructional ones where some strength
is required to achieve any of the structures
previously described. These are ‘big’ joints,
not those used in furniture, even though they are
basically the same. Think of oak-framed buildings
and the way in which these are jointed together.
Apart from mortise & tenon, dovetail and halving
joints, for example, they’ll include bird’s mouth,
cogged, fish plate, saddle, scarfed etc., etc.

Carroty
A general term that can be applied to wood
that is short-grained or pithy.

Cascamite

One of the best known powdered resin

adhesives on the market, Cascamite has been

used extensively for some time. Once mixed

with cold water, to a thick cream-like consistency,

it will set hard and rigid once applied and left

to cure. This is one of the glues that does not

‘creep’ or move under pressure.

Case hardening

Case hardening is a drying defect in timber. It’s

created when the outer layer of, say, a plank, has

been dried quicker than the core, thus making

a harder outside case or shell. Effectively the

outside has shrunk more than the middle and

this sets up tensions within the wood structure.

These tensions can lead to distortion when larger

pieces are cut down into smaller pieces. It can be

fixed, however. The outer cellular layers need to

have their moisture content increased to relieve

the tension. A longer drying cycle then needs

to be introduced that will help remove the core

moisture but equalise the spread of moisture

throughout the whole of the affected plank or

planks. A quick test for case hardening is to cut a

cross-sectional piece from a suspect plank then

remove the middle from one edge leaving two

long fingers attached to the remaining edge. If the

ends of the two ‘fingers’ curl inwards, towards

the middle, the piece is case hardened. Resawing

case hardened material into smaller pieces can

be difficult. Because of the tensions it will tend to

bind on the saw blade as it distorts and this will

probably create saw burn on the cut faces without

taking into account the waste through bowing

or twisting, etc.

Casement window

A window that has an opening casement, be it

hinged or pivoted, is called a casement window.

Casings

Casings are another phrase used to describe

window or door linings. These are the outer

framework into which the window or door will fit.

The phrase can also be applied to the side boxes

of sash windows in which the weights are housed.

Cast

A plank of wood might have a cast in it, which

means it could be twisted or bowed.

Round pivot window

Photograph courtesy of Marvin Windows

Catherine wheel window

Another name for a round window but one that

has radiating bars like the spokes of a wheel.