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UNIT OF MEASUREMENT
The unit of measurement used in Practical Woodworking is millimetres (mm). It is essential that millimetres are used rather than centimetres as millimetres are a more accurate unit of measurement. The sizes in working drawings you will be using to make your models throughout the course will be stated in mm.
DATUM EDGE
DATUM EDGE
When marking out on wood, measurements should be taken from a datum. A datum edge is a flat or straight edge from which all measurements should be taken, otherwise you're in danger of making cumulative errors. The face edge should be carefully chosen, making sure it is flat with a straight edge, then it is marked with a small symbol for identification purpises. A face side is then selected which is at right angles to the face edge. All measurements are then taken from this side and/or edge.
WORKING TO TOLERANCE
In the case of Practical Woodworking, the tolerance of a component is ther permissible amount of variation to the size given in a working drawing or a gap between a joint. The tolarance that you will be expected to work to for National 5 is ± 1mm (plus or minus 1mm). Working to this tolerance will ensure that different parts of your model fit together correctly and that the final model looks good. The types of tasks you will have to do to this given tolerance are marking out, planing, drilling to a given position, sanding to a line and making sure that any gaps between joints dont exceed 1mm.
Candidates are required to demonstrate the ability to use the measuring & marking out tools shown.
STEEL RULE
TAPE MEASURE
TRY SQUARE
MARKING GAUGE
MARKING KNIFE
MORTISE GAUGE
CUTTING GAUGE
SLIDING BEVEL
TEMPLATE
DOVETAIL TEMPLATE
OUTSIDE CALIPERS
For more information, see the Measuring & marking out notes in the theory tab.
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