Carpentry and Joinery
What this domain tests
This domain tests timber selection and seasoning, the standard joints used in frames and furniture, and the correct fixing and sizing of doors and windows.
Core rules and concepts
- Timber: well-seasoned wood has 10–12% moisture content; seasoning is done in air or in a kiln; defects to reject are knots, shakes, warping and sapwood.
- Joints: mortise and tenon for door frames and legs; dovetail for drawers; halving for crossing members; rebate for glass and panel edges; tongue and groove for flooring; butt joint with dowel or screw for simple work.
- Saws: ripsaw along the grain, crosscut saw across it, tenon saw for fine joint cutting.
- Door: chowkhat (frame) with holdfasts embedded in masonry, shutter, hinges, tower bolt, aldrops, handles; frame section commonly 63 × 100 mm for a 900 mm door.
- Windows: 1200 × 1200 mm typical; sill slope outward to drain water; putty or glazing bead for glass.
- Fixing: screws hold better than nails in hardwood; drill a pilot hole; glue joints and clamp until set.
Worked example
A door opening 1000 × 2100 mm with frame section 63 × 100 mm. The two vertical members stand full height at 2100 mm each. The head rail fits between them: 1000 − (2 × 63) = 874 mm. Cutting the head to the full 1000 mm is a common site error that forces the frame out of the opening.
Traps that cost marks
Using a crosscut saw for ripping; sizing the frame to the shutter instead of the opening; forgetting holdfasts or leaving them loose; applying polish before the surface is filled and sanded; joints glued without clamping.