Stock Forms, Types, and Standard Sizes

This lesson covers the stock forms, types, and standard sizes in which materials are supplied, as required by AQA GCSE D&T (8552), Section 3.2.6. Understanding stock forms is essential for practical work (knowing what to order) and for the exam (specifying appropriate starting materials for a given manufacturing process).

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What Are Stock Forms?

Stock forms are the standard shapes and sizes in which raw materials are supplied by manufacturers and suppliers. Using standard stock forms is more economical than having custom sizes produced, and they are readily available from suppliers.

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Timber Stock Forms

Stock Form	Description	Common Sizes
Rough sawn	Timber sawn from the log but not planed; rough surfaces with visible saw marks	Various; oversized compared to PAR equivalent
Planed all round (PAR)	All four faces planed smooth and parallel; ready to use	12x44, 20x44, 20x70, 20x95, 20x145, 44x44, 44x70, 44x95, 44x145 mm (common finished sizes)
Planed square edge (PSE)	Two faces and one or two edges planed	Similar to PAR
Dowel rod	Round cross-section, smooth	3, 4, 5, 6, 8, 10, 12, 15, 20, 25 mm diameter
Mouldings	Shaped cross-sections	Skirting, architrave, dado rail, picture rail, scotia, quadrant — standard profiles

Manufactured Board Stock Forms

Board	Standard Sheet Size	Common Thicknesses
MDF	2440 x 1220 mm (8ft x 4ft)	3, 6, 9, 12, 15, 18, 25 mm
Plywood	2440 x 1220 mm	3, 4, 6, 9, 12, 18, 25 mm
Chipboard	2440 x 1220 mm	12, 15, 18, 22, 25 mm
Hardboard	2440 x 1220 mm	3, 6 mm

AQA Exam Tip: The standard sheet size for manufactured boards (2440 x 1220 mm — equivalent to 8 feet x 4 feet) is worth knowing. If an exam question asks about material requirements for a project, you can reference this standard size to calculate how many sheets you need and estimate waste.

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Metal Stock Forms

Stock Form	Cross-Section	Common Materials	Common Use
Sheet	Flat, thin (0.5-3 mm)	Mild steel, aluminium, copper, brass	Enclosures, brackets, panels, decorative work
Plate	Flat, thick (3 mm+)	Mild steel, aluminium	Structural steelwork, base plates, heavy fabrication
Flat bar	Rectangular solid cross-section	Mild steel, aluminium, brass	Brackets, frames, structural components
Round bar	Circular solid cross-section	Mild steel, aluminium, brass, stainless steel	Shafts, pins, turned components (lathe work)
Square bar	Square solid cross-section	Mild steel, aluminium	Structural frames, handles
Hexagonal bar	Hexagonal solid cross-section	Mild steel, brass, stainless steel	Bolts, nuts, fittings (the hex shape allows spanners to grip)
Round tube	Circular hollow cross-section	Mild steel, aluminium, copper, stainless steel	Bicycle frames, furniture, plumbing, handrails
Square tube	Square hollow cross-section	Mild steel, aluminium	Furniture frames, structural framing, go-kart chassis
Rectangular tube	Rectangular hollow cross-section	Mild steel, aluminium	Structural members, frames
Angle	L-shaped cross-section	Mild steel, aluminium	Shelf brackets, frame construction, edging
Wire	Very thin, round, flexible	Mild steel, copper, brass, stainless steel, aluminium	Electrical wiring, fencing, springs, sculpture
Extrusion	Custom complex cross-section	Aluminium (most common)	Window frames, heat sinks, curtain tracks, structural profiles

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