Carpentry, Joinery and Woodwork
This domain tests timber selection, seasoning, hand and machine operations, and the joints that make a door, window or cabinet rigid and square.
Timber and seasoning
Hardwoods such as teak, sal and shisham suit frames and shutters; softwoods such as deodar, pine and chir suit general work and shuttering. Defects include knots, shakes, warp, cup, bow, twist, sapwood and insect attack. Seasoning brings moisture down to about 10 to 12% for joinery so finished members do not shrink and split. Preservative treatment extends life, especially where timber touches the ground.
Joints
- Mortise and tenon for frame joints in door stiles and rails.
- Dovetail for drawer corners, which resists pulling apart.
- Halving for crossing members that finish flush.
- Housing or dado for a shelf into an upright.
- Dowel and biscuit for modern edge joints. Glue plus a mechanical fixing is normal; the joint must be tight, square and flush.
Worked example
A door shutter 900 mm wide and 2100 mm high with 50 mm stiles, 100 mm top and bottom rails, and a 150 mm lock rail. Internal width between stiles = 900 - 50 - 50 = 800 mm, so each rail is cut 800 mm long plus any tenon. The panel width is 800 mm and its height = 2100 - 100 - 150 minus rebate allowances.
Traps
Measuring a rail to the full door width, planing against the grain, using unseasoned timber and blaming the paint, and mixing up rip sawing along the grain with cross-cutting across it.