I'll need to sharpen my plane...

[CWatters]

The manual for this mitre saw says...

http://www.screwfix.com/prods/49979/Pow ... Mitre-Saw#

Holes are provided in the saw fence to attach an auxiliary wood fence. This fence is to be constructed of straight wood approximately 19.05 mm thick by 63.5 mm high by 457.2 mm long

.

Good job it's only got to be approximately 19.05mm.

 

[SketchUp Guru]

I suppose you could measure it in old money and make 3/4" x 2-1/2" high and 18" long.

 

[Smudger]

A bit defeatist, don't you think?

Our woodwork technician told the story of a new teacher who had an engineering background. He was planing a piece of timber to size - to the nearest thou. Took ages whilst the technicians looked on with slightly silly smiles on their faces. Then he went for a cup of tea, and when he came back it was smaller...
The organic nature of wood had to be carefully explained to him.
But it was OK - it got bigger again later in the day.