Shaping & Cutting Timber

Converting Timber from Log to Board

Before timber reaches a workshop it must be converted — cut from the round log into usable sections. The conversion method affects the stability, appearance and cost of the resulting boards. Two principal methods are used commercially:

• Through-and-through (plain) sawing — the log is sliced in parallel cuts from one side to the other, like a loaf of bread. It is the fastest and most economical method, producing the widest boards with the least waste. However, boards from the outer sections of the log have grain rings running at a low angle to the face, making them prone to conversion failure (cupping) as they dry.
• Quarter sawing — the log is first quartered lengthways, then each quarter is cut so the saw cuts radially, at 60–90° to the growth rings on the face of the board. Quarter-sawn boards are more stable (less prone to cupping), show the attractive medullary ray figure in species such as oak, and wear more evenly on flooring. The method wastes more timber and takes longer, so quarter-sawn timber commands a price premium.

Marking Out

Accurate marking out transfers measurements from a design drawing onto the workpiece before cutting. The process begins by identifying the face side and face edge — the two reference surfaces from which all measurements are taken. These are marked with a face mark (a looping pencil mark) and a face edge mark (a V pointing to the face side).

• Try square — used to mark and check lines at exactly 90° to the face edge; essential for all cross-grain cutting lines.
• Marking gauge — a fence and adjustable spur used to scribe a line parallel to the face edge, for example when marking out a rebate or tenon shoulder width.
• Mortise gauge — a double-spur version of the marking gauge, used to mark both sides of a mortise or tenon simultaneously, ensuring both members match.
• Marking knife — severs the wood fibres cleanly at the cut line, producing a finer and more accurate line than a pencil; essential where a chisel or saw will start exactly at the line.

Wastage Processes: Sawing

Wastage processes remove material by cutting. Sawing is the primary method for both conversion and workshop dimensioning. Hand saws are classified by the number of teeth per 25 mm (teeth per inch, tpi) and the tooth geometry:

• Rip saw — large, widely spaced teeth with little set; cuts along the grain by a chiselling action. Not suitable for cross-grain cutting.
• Cross-cut saw — fine, angled teeth that sever the wood fibres cleanly when cutting across the grain. The most common general-purpose hand saw.
• Tenon (back) saw — a reinforced back keeps the blade rigid for accurate straight cuts; used for jointing and fine work. Available in rip and cross-cut tooth patterns. Used with a bench hook.
• Coping saw / fret saw — a thin blade under tension in a U-frame; used for internal curves and shapes in thin timber and sheet material.
• Jigsaw (powered) — a reciprocating blade that can follow curved and straight lines in timber and manufactured boards; available in a range of blade types for different materials.
• Circular saw (table saw / track saw) — rapidly rips and cross-cuts large sheets of manufactured board in production environments. Requires guards, extraction and trained operators.
• Band saw — a continuous loop blade running around two wheels; cuts curved shapes and thick sections; used for re-sawing (splitting thick timber into thinner sections).

Planing, Chiselling and Drilling

After sawing, surfaces are refined and waste removed using planes and chisels:

• Jack plane — general-purpose plane for removing saw marks and roughly truing surfaces.
• Smoothing plane — shorter sole for final surface preparation before finishing; produces a fine shaving and smooth surface.
• Shoulder plane / rebate plane — cuts rebates and the shoulders of tenons cleanly to the line.
• Firmer chisel — used for paring (removing thin shavings by hand) and for chopping waste from mortises. Always work from the face inward to avoid splitting out the back of the work.
• Mallet — used with a chisel to chop mortises and remove waste across the grain; not a hammer, which would damage the chisel handle.
• Pillar drill / bench drill — a vertical-axis drill press that bores holes accurately at 90° to the surface; essential for dowel joints and hinge recesses. Paired with Forstner bits for clean flat-bottomed holes in timber.

CNC Routing in Timber Production

Computer Numerical Control (CNC) routing is the dominant production process for shaped timber components in modern furniture and joinery manufacture. A CNC router moves a spinning cutter in X, Y and Z axes following a digital design file (typically output from CAD software). Advantages over manual routing include:

• Accuracy — tolerances of ±0.1 mm are achievable, far beyond hand-tool capability; identical components can be reproduced across a batch of thousands.
• Speed — large sheets of MDF or plywood can be fully nested and cut in minutes with minimal operator involvement.
• Complexity — complex curved profiles, pockets, joints (including box joints and even basic dovetails) can all be cut in a single setup, reducing handling.
• Nesting — CAD/CAM software automatically arranges components on a sheet to minimise off-cuts, reducing material waste.