Heat & temper colours for steel (temperatures in Farenheit, the UK standard at the time).

To jog your memory, °F = (°C x 1.8) + 32

British Standard Whitworth thread table for ¼" and upwards. The Meccano system uses a 5/32" Whitworth thread which was in common usage in the early 1900's for household fittings! Not shown on the engineers table, it is 32 t.p.i.

B.S.F., B.S.P. & B.A. thread data

Letter & Number Drill, and various inch Wire gauges - British & American. Hornby chose to use Imp. Gauge 8 for the rod-axle gauge in his "Mechanics Made Easy", subsequently "Meccano" outfits.