In 1961, a blacksmith from Sheffield, John Brailsford, then a teacher
of engineering technology, created the ever first purpose designed
nut, the Acorn. Three sizes (1 inch, ¾ inch and 5/8 inch)
were turned on a lathe from extruded aluminium alloy. John Brailsford
also tried Tufnol (a resin bonded fibre used by Rolls Royce or Hoover
for making light weight, silent gears) and brass for their different
properties of hardness. Since the Acorn had a machine nut sitting
on its top and threaded on the same sling, this « nest of
nuts » offered two options, the machine nut or the Acorn.
They were probably the first nuts to be marketed in England, by
the Roger Turner Mountain Shop in Nottingham.
Most of the difficult cracks which were climbed by hand-jam and
layback techniques needed however a wider nut. After measuring some
of them, John Brailsford, always him, made models in balsa wood
in the form of truncated, oblong pyramids. A Derby company, Coronet
Tools, specialising in aluminium casting made six prototypes in
L.M. 6 in which John Brailsford drilled two holes and created a
radius to join these holes.