Kodi’s Joinery Companion
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Beginner joinery

Measuring and
marking out

Read the scale, keep track of units, and put your marks in the right place. Build the basics before you cut.

Measure. Mark. Check.

Use a clear reference end. Write the unit. Check the measurement before making a cut.

6 topics · 18 practice questions

Progress is kept for this visit. Take the topics in order, or choose one to practise.

Read a metric tape measure

Each small interval is 1 millimetre (mm). Ten millimetres make 1 centimetre (cm). On this tape, the numbered long marks show centimetres and the middle-length marks show 5 mm. Read straight down from the end of the timber to the scale.

Start at zero when you can. If the timber starts at another mark, subtract the start reading from the end reading. Mark a thin pencil line at the required tick; a thick line makes the position less clear.

Worked example

The timber starts at zero and ends 7 small intervals after the 3 cm mark. What is its length?

Timber aligned with a metric tapeThe timber starts at the 0 cm mark and ends at the 3 cm mark plus 7 small intervals. Each small interval is 1 mm. Read the difference between the start and end.Timber0123456cm
Numbers show cm. Each small interval is 1 mm. The red line shows the end. Enlarge the tape for a closer look.
30 mm+7 mm=37 mm30\,\text{mm} + 7\,\text{mm} = 37\,\text{mm}

3 cm is 30 mm. Count the intervals after that mark, then add 7 mm.

Your turn

Question 1 of 3

The timber starts at zero. Read its length from the tape below.

Timber aligned with a metric tapeThe timber starts at the 0 cm mark and ends at the 4 cm mark plus 6 small intervals. Each small interval is 1 mm. Read the difference between the start and end.Timber0123456cm
Numbers show cm. Each small interval is 1 mm. The red line shows the end. Enlarge the tape for a closer look.

A number uses mm. You can also enter an equivalent length with mm, cm or m, using a decimal point.

Continue to metric units

Convert mm, cm and metres

1 cm = 10 mm. 1 metre (m) = 100 cm = 1,000 mm. Multiply when converting to a smaller unit; divide when converting to a larger unit. The physical length stays the same.

Write the unit next to every measurement. 2.4 m and 2.4 mm describe very different lengths.

Worked example

Convert a 1.25 m length of timber to millimetres.

1 m=100 cm=1,000 mm
1.25 m×1000=1250 mm1.25\,\text{m} \times 1000 = 1250\,\text{mm}

Each metre contains 1,000 mm, so multiply the number of metres by 1,000.

Your turn

Question 1 of 3

Convert 36 cm to millimetres.

A number uses mm. You can also enter an equivalent length with mm, cm or m, using a decimal point.

Continue to centre marks

Find the centre of a length

The centre is halfway along a length. Divide the full length by 2, then measure that distance from one end. The two halves should be equal.

Use the same reference end for your measurements. Check the centre mark from the other end: the distance should match.

Worked example

Where is the centre of a 740 mm rail, measured from its left end?

A centre mark divides the rail into two halvesThe rail is 740 mm long. Each section is 370 mm. Internal marks are measured from the left end.Full length: 740 mm370 mm370 mm0370740Mark positions in mm from the left end
Schematic diagram; gaps and cut widths may be enlarged for clarity. Use the stated measurements. Enlarge for a closer look.
740 mm÷2=370 mm740\,\text{mm} \div 2 = 370\,\text{mm}

Mark 370 mm from the left end. There is also 370 mm from that mark to the right end.

Your turn

Question 1 of 3

A rail is 960 mm long. How far from the left end is its centre?

A number uses mm. You can also enter an equivalent length with mm, cm or m, using a decimal point.

Continue to equal sections

Mark equal sections

To mark a length into equal sections, divide the full length by the number of sections. Measure each mark from the same end: one section length, two section lengths, and so on. Four sections need three internal marks.

These are layout marks only; no material is removed. Equal gaps between separate objects are a different calculation: first subtract the object widths, then count the actual gaps.

Worked example

Mark a 900 mm rail into 3 equal sections. No cuts are made.

A rail divided into 3 equal sectionsThe rail is 900 mm long. Each section is 300 mm. Internal marks are measured from the left end.Full length: 900 mm300 mm300 mm300 mm0300600900Mark positions in mm from the left end
Schematic diagram; gaps and cut widths may be enlarged for clarity. Use the stated measurements. Enlarge for a closer look.
900 mm÷3=300 mm900\,\text{mm} \div 3 = 300\,\text{mm}

Each section is 300 mm. Make internal marks at 300 mm and 600 mm from the left end. The far end is 900 mm.

Your turn

Question 1 of 3

Mark a 1,200 mm rail into 4 equal sections. No cuts are made. What is the length of each section?

A number uses mm. You can also enter an equivalent length with mm, cm or m, using a decimal point.

Continue to gaps & clearance

Understand gaps and clearances

A clearance is space deliberately left between parts. Follow the gap specified in the drawing or question. A gap at each side uses space twice. For equal gaps between objects, subtract all object widths before dividing the remaining space by the number of gaps.

The clearances here are specified for these exercises only. Real clearances depend on the design, materials and fitting instructions; these numbers are not universal installation rules.

Worked example

An opening is 600 mm wide. The drawing specifies a 3 mm gap at the left and a 3 mm gap at the right. How wide should the panel be?

A panel with a specified clearance at each sideAn opening 600 mm wide contains a panel with a 3 mm gap at each side.Opening: 600 mmPanel: 594 mm3 mm3 mm
Schematic diagram; gaps and cut widths may be enlarged for clarity. Use the stated measurements. Enlarge for a closer look.
600 mm−2×3 mm=594 mm600\,\text{mm} - 2 \times 3\,\text{mm} = 594\,\text{mm}

The two gaps total 6 mm. Subtract both gaps from the opening width.

Your turn

Question 1 of 3

An opening is 800 mm wide. For this exercise, leave a 2 mm gap on each side of a panel. What panel width is needed?

A number uses mm. You can also enter an equivalent length with mm, cm or m, using a decimal point.

Continue to saw kerf

Allow for the saw kerf

Kerf is the width of material a saw removes in a cut. A cut does not just split a pencil line: it uses some timber. Multiply the stated kerf by the stated number of cuts, then account for that loss as well as the finished piece lengths.

For a finished piece, put the saw cut on the waste side of the mark so the kept piece retains its intended length. Count every cut, including end trimming when specified.

Worked example

A 1,000 mm stock length has already-square ends. Cut off two finished 300 mm pieces using exactly 2 cuts, each with a 3 mm kerf. No extra trimming is done. How long is the offcut?

Two saw cuts remove material from a stock lengthA 1,000 mm stock length becomes two 300 mm pieces, two 3 mm kerfs, and a 394 mm offcut. The red slots represent the material removed by exactly two cuts. No additional trimming.1,000 mm stock; exactly 2 cuts300 mm300 mm394 mm3 mm kerf3 mm kerf
Schematic diagram; gaps and cut widths may be enlarged for clarity. Use the stated measurements. Enlarge for a closer look.
1000 mm−2×300 mm−2×3 mm=394 mm1000\,\text{mm} - 2 \times 300\,\text{mm} - 2 \times 3\,\text{mm} = 394\,\text{mm}

The kept pieces use 600 mm. The two cuts remove another 6 mm. The offcut is 394 mm.

Your turn

Question 1 of 3

Make exactly 3 cuts with a kerf of 2 mm per cut. There are no other cuts or end trims. What total length of material do the cuts remove?

A number uses mm. You can also enter an equivalent length with mm, cm or m, using a decimal point.

Before you cut

Check the drawing, reference end, units, mark position and waste side. Remember that layout marks and finished pieces after cutting can need different calculations.

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