Frank Stacey laid this down on his screen :
I want to remove a bolt which takes a 4mm hex alan key - well it's not quite
that simple. The hex hole has a central pin which prevents the insertion of
a standard alan key. It may be a useful security feature but nobody knows
the wherabouts of a suitable key so it's a problem.

Ayone know if suitable alan keys can be obtained anywhere? I can't find such
things via screwfix.

The usual solution is to insert a suitable flat bladed screwdriver
alongside the pin and break the pin off by gradually prying the pin
from side to side.

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Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk