NSSCO Woodwork 6190 cheat sheet

Seasoning reduces moisture content to about 10-15% for interior work; timber used green shrinks, warps and splits as it dries.

Conversion methods: through-and-through (plain sawn) gives wide boards with figure but more cupping; quarter sawing gives stable boards with straight grain and less movement.

Natural defects: shakes are separations along the grain; knots are branch bases; reaction wood (compression in softwoods, tension in hardwoods) causes severe distortion when machined.

Movement rule: tangential shrinkage is roughly twice radial shrinkage; design frames and panels to allow cross-grain movement of about 5-8 mm per metre of width.

Manufactured boards: plywood (alternating veneers, strong and stable), blockboard (softwood core strips), chipboard (resin-bonded chips, weak edges), MDF (fine fibres, excellent for shaping and routing), hardboard (wet-process fibre, one smooth face).

Adhesive selection: PVA for interior joints and assembly; cross-linking PVA or polyurethane for damp or exterior conditions; urea-formaldehyde for veneering and laminating; contact adhesive for plastic laminate; epoxy for gap filling and mixed materials.

Glue joint strength depends on close fit, clean surfaces, correct clamp pressure and adequate open and clamp times; starved or over-clamped joints fail at the glue line.

Finishes: sanding sealer fills pores before topcoat; French polish (shellac) gives high gloss but poor water and heat resistance; polyurethane varnish is durable for interior work; Danish oil penetrates and is easily refreshed; wood stain changes colour but gives no protection.

Sharpening angles: bench plane irons and chisels about 25 degrees primary bevel with a 30 degree micro-bevel; bevel-up planes and low-angle blocks use lower bevels; mortise chisels use a steeper 30-35 degree bevel for edge strength.

Plane set-up order: flatten the back, hone the bevel, fit the cap iron close to the edge (about 0.5 mm) for fine work, set the mouth fine for smoothing and wide for thick shavings.

Saw selection: crosscut saw has 10-12 tpi with filed fleam teeth for severing fibres; rip saw has 4-7 tpi with chisel teeth for cutting along the grain; tenon saw about 12-14 tpi for accurate joinery.

Marking tools: try square for squareness, marking gauge for lines parallel to a face side and face edge, mortise gauge for twin lines, sliding bevel for angles other than 90 degrees.

Portable circular saw: blade depth set so teeth just clear the underside of the workpiece (about 3-5 mm proud); riving knife fitted; push direction against blade rotation; never remove the guard.

Portable router: feed left to right along an edge (against rotation) for a climb-free cut; take shallow passes of 2-3 mm depth; unplug before changing cutters, and fit cutters fully into the collet.

Maintenance: keep plane soles flat and waxed, oil metal surfaces against rust, clean resin from saw blades with solvent, check power leads and plugs for damage before use, and replace blunt or chipped cutters rather than forcing them.

Personal protection: eye protection for all machining and chiselling, dust mask for sanding and MDF, hearing protection for routers and planers, and no loose clothing or gloves near rotating cutters.

Circular saw bench: riving knife aligned with the blade, crown guard set to workpiece thickness, push stick for stock under 300 mm wide, and never reach over the blade.

Surface planer: reference face flattened first on the infeed table, then the face edge squared on the fence; tables set level with the cutter block; guard set to expose only the width of cut; minimum stock length about 300 mm.

Thicknesser: cuts parallel to the planed face, so always plane a flat face first; maximum depth of cut around 1-2 mm per pass; feed against the rotation of the cutter block.

Band saw: blade width determines the minimum radius of cut (narrow blade for tight curves); upper guide set about 3-5 mm above the work; blade tension and tracking checked before use.

Mortiser: chisel and bit clearance about 0.5-1 mm; cut from both ends of a mortise or in overlapping plunges; lock the workpiece securely and keep hands clear of the chisel.

Router table and spindle moulder: cutter rotation feeds the work right to left on a table; use a false fence for narrow work and a push block; never climb-cut freehand.

Lathe: workpiece must be balanced and rough-turned at slow speed; tool rest set close to the work (about 3 mm) and adjusted as diameter reduces; check for cracks and loose knots before mounting.

Machine safety rules: isolate before changing blades or cutters, use dust extraction, never wear loose sleeves or jewellery, and keep the floor area around each machine clear.

Joint classes: widening joints (dowel, biscuit, loose tongue, rub joint), lengthening joints (scarf, finger, half-lap), and framing joints (mortise and tenon, dovetail, halving, bridle).

Mortise and tenon proportions: tenon thickness about one third of the rail thickness; mortise length about two thirds of the rail width; haunch on a tenon prevents the rail twisting and closes the shoulder.

Dovetail: tails cut on the pin piece with a dovetail angle of about 1:6 (hardwood) or 1:8 (softwood); pins and tails marked directly from the workpiece; through dovetails for boxes, lapped dovetails for drawer fronts.

Carcass construction: rebate or groove for back panels, stopped housings or dados for shelves, and corner joints such as comb, mitre with spline, or dowel.

Frame construction: stiles run vertically and rails horizontally; a haunched mortise and tenon is used where a rail meets a grooved stile, and a bare-faced tenon where the shoulder must be flush.

Glue-up sequence: dry assemble first, apply glue to both surfaces, clamp square with diagonals checked, and remove squeeze-out before it cures.

Fasteners and fittings: countersink screws in hardwood or use a pilot hole to avoid splitting; confirm the hinge type, knuckle clearance and overlay before machining the door.

Face side and face edge marks (the 'working face') are the datum from which all other faces are squared, marked and machined.

Setting out uses full-size rods or drawings to transfer dimensions; marking out transfers those dimensions to the timber with gauge, square and knife line.

Pythagoras: for a right angle, 3-4-5 triangle (or multiples) gives a square corner; diagonal check on a carcass confirms squareness.

Board foot: 1 board foot = 144 cubic inches = 1 in x 12 in x 12 in; metric timber is priced per cubic metre (m3), calculated as length x width x thickness in metres.

Waste allowance: add 10-15% for general waste and up to 25-30% for short lengths, figured timber or complex cutting lists.

Circle and arc calculations: circumference = pi x diameter; arc length = (angle/360) x circumference; chord and rise allow radius calculation for curved work.

Conversion factors: 1 inch = 25.4 mm; 1 foot = 304.8 mm; 1 m2 = 10.76 ft2; 1 kg = 2.205 lb.

Cutting list order: part name, quantity, finished size (length x width x thickness), material, and notes on grain direction and joint allowances.

Lathe axes: spindle turning runs between centres along the grain; faceplate turning mounts the work on a screw chuck or faceplate across the grain for bowls and platters.

Turning tools: roughing gouge for reducing square stock to a cylinder; spindle gouge for beads and coves; skew chisel for planing cuts and V-grooves; parting tool for sizing and separating; bowl gouge for end-grain hollowing.

Bevel rubbing: the bevel supports the cut and controls depth; cutting above centre on spindle work and at centre height on faceplate work.

Speeds: large diameter and out-of-balance work at low speed; small diameter spindle work at higher speed; rule of thumb, slower for bigger and rougher blanks.

Shaping by hand: spokeshave for curved work, rasp and file for fairing curves, scraper for removing tear-out, and abrasive paper wrapped on a block for consistent profiles.

Hollowing and routing: router cutters for grooves, rebates and mouldings; template guides and jigs for repeatable curved shapes; climb-cutting avoided on freehand routing.

Safety: check stock for splits and loose knots, mount between centres securely, set the tool rest close to the work, and never leave the lathe running unattended.

Design process: brief, research, specification, working drawings, cutting list, prototype or mock joint, manufacture, finish and evaluation.

Working drawings: orthographic views (plan, front and side elevation) plus isometric or exploded detail; scale 1:1 for detail, 1:5 or 1:10 for furniture, 1:50 or 1:100 for room layouts.

Costing formula: total cost = materials + labour (hours x rate) + overheads + finishing + contingency (typically 10%).

Material costing: calculate volume in m3 and multiply by unit price per m3; add sheet material by area (m2) and allow for wastage in the cutting plan.

Critical path: identify tasks that must precede others (setting out before cutting, gluing before finishing) and allow drying and curing times in the schedule.

Design constraints: function and ergonomics (seat height about 450 mm, table height about 750 mm), strength, available materials, cost, and the required finish.

Evaluation criteria: fitness for purpose, accuracy to drawing, quality of joints and finish, safety in use, and cost against budget.

Risk assessment: identify the hazard, decide who may be harmed and how, evaluate the risk, record significant findings, and review controls.

Hierarchy of control: eliminate, substitute, engineering controls (guards, extraction), administrative controls (training, signage), then personal protective equipment last.

Dust: wood dust is a respiratory hazard and a fire risk; use local exhaust ventilation at each machine, keep dust to a minimum, and never sweep dust into the air with compressed air.

COSHH: finishes, adhesives and solvents need data sheets, correct storage, ventilation and suitable gloves; solvent-based products are flammable and must be kept away from ignition.

Electrical safety: portable tools on RCD protection, PAT testing at intervals, no damaged leads, and no trailing cables across walkways.

Workshop layout: machines grouped by function, clear walkways, storage for timber off the floor, designated finishing area with ventilation, and a first-aid point with fire extinguishers (CO2 or dry powder for electrical fires).

Housekeeping: clear offcuts and shavings at the end of each session, store sharp tools in racks or rolls, and lock away hazardous substances.

Sequence of operations: set out, cut to size, plane and square, mark joints, cut joints, dry fit, glue and clamp, clean up, then finish.

Squaring procedure: plane the face side flat, square the face edge to it, gauge the required thickness and width from those faces, then plane to the gauge lines.

Cutting a mortise: mark the mortise from the tenon, drill out waste with a bit smaller than the mortise width, then chop square with a mortise chisel, working from both faces to avoid breakout.

Tenon cutting: mark from the mortise, cut the shoulders first with a tenon saw, then remove the cheeks, checking fit and squareness before gluing.

Finishing sequence: raise the grain with a damp cloth, sand through grits (e.g. 80, 120, 180, 240), remove dust, apply sealer, then apply the chosen topcoat in thin coats.

Quality checks: test diagonals for square, test joints for a close fit with no gaps, check flatness with a straightedge, and check that dimensions match the drawing within tolerance (about 1 mm).

Project documentation: cutting list, working drawings, risk assessment, cost sheet, and an evaluation of the finished item against the brief.