Timber Stock Forms and Quantity Calculations
Timber comes in standard stock forms and sizes. Learn planks, dowels, mouldings and sheet materials, the difference between rough sawn and planed timber, and how to calculate how much to buy.
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Buying timber wisely 🪵
Timber is not sold in any shape you like - it comes in standard **stock forms** and **sizes**. Knowing them lets you choose the right material and work out exactly how much to buy. This module covers the stock forms, the difference between rough sawn and planed timber, and the **quantity calculations** that stop you over- or under-ordering.
The words you need 🔑
Four ideas run through the topic:
Match each stock form to its description 🔗
- Plank
- Dowel
- Moulding
- Sheet material
- A wide, flat length of solid timber
- A round rod, useful for pegs and rails
- A shaped strip, such as skirting or beading
- A large flat board like plywood or MDF
Why is it smaller? 📏
Why is a piece of planed timber smaller than its nominal size?
- Planing removes material from each face
- It shrinks while sitting in storage
- It was measured incorrectly at the mill
- It is simply a cheaper grade of wood
Working out how much to buy 🧮
To calculate the timber for a job: 1. **Total length** = number of pieces x length of each 2. **Stock lengths** = total length divided by the stock length, then **rounded UP** to a whole number 3. **Cost** = number of stock lengths x price each Always round the number of lengths **up** - you cannot buy a fraction of a length.
Total length needed ➕
An interactive activity.
Which are sheet materials? ✅
Select the TWO that are manufactured sheet materials.
- Plywood
- MDF
- Dowel
- Moulding
Nominal to actual 🪚
An interactive activity.
Rough sawn versus PAR ⚖️
The same timber can be bought straight from the saw or smoothed all round.
How many lengths? 🔢
An interactive activity.
Put it together 🧱
Timber is sold in stock _____ such as planks and dowels. Rough _____ timber is cheaper; _____ timber is smoother but smaller than its _____ size. A _____ list records every piece you need.
Order the calculation 🪜
An interactive activity.
In the workshop 🧭
An interactive activity.
The grade-9 habit 🌟
Top answers **build a cutting list**, total the length, and divide by the stock length - always **rounding up** to whole lengths, because you cannot buy part of one. They also **allow for planing**: if a design needs a finished size, remember PAR arrives a few millimetres under its nominal size. Cutting list, round up, allow for the actual size - top band.