Ross Herbert wrote:

Here is a typical 3000 type telephony relay as used in UK and
Australia in SxS. http://www.britishtelephones.com/autorel.htm

In fact this particular picture appears to show the winding bobbin
with a copper front cheek which is the smallest armature end slug of
all.


The common GPO 3000 had the copper slug embedded into the armature. They
would work on AC but were much happier on DC

My father manufactured amusement machines and I entered the business
even before leaving school.

There are still many GPO type relays and boxes of contact blades kicking
around in my mothers house. (Also Quite a lot of those wonderful
uniselectors). The ability to strip them down and reassemble them in
many permutations of contact arrangement, made them a wonderfully
versatile device, and pretty reliable also.

Ron(UK)