Strange screw heads

[John Ross]

Hi David,
They are a Canadian invention, called a Robertson. There are 5 sizes that I
have.
If he had let Ford use them, or sold the patent to them, as Ford wanted,
they
would probably be the most widely used screw, today.  But Robertson wanted
it all,
so they stayed small.
Regards,
John M. Ross
Windsor, Nova Scotia, Canada
piano.tech@ns.sympatico.ca
----- Original Message -----
From: "David Boyce" <David@bouncer.force9.co.uk>
To: <pianotech@ptg.org>
Sent: Saturday, July 28, 2001 2:50 PM
Subject: Strange screw heads


> Hi folks,
>
> I wonder if anyone (in the UK?) has come across action screws like these?
> I tuned for a new customer yesterday, an old straight-strung upright,
circa
> 1920, pretty standard cheap quality English upright.  I took the action
> out, and noticed that the flange screws had odd heads.
> I pride myself on having every kind of screwdriver - flat, Philips, Torx,
> Hex, Pozidrive, Security Torx etc.  These screws, however, had heads with
> SQUARE holes.  Looked like Hex heads at first, but square.  A new one on
> me!
>
> Best regards,
>
> David.
>
> P.S. I got one out using just an ordinary flat screwdriver placed
> diagonally in the hole.
>
>