Wednesday, July 6, 2022

A little 'B-key' or Burroughs case-key

This is something every owner of an older Burroughs calculator or adding machine will want.

The Burroughs company did not want users to poke around the internals of their adding machines. To discourage such 'tinkering', the cases were locked and needed a 'B-key' to unlock. It's possible to jimmy the lock (a thin blade between base and cover to push the latch away) or sometimes just lots of jiggling to get the cover off - but with a B-key it becomes so much easier :-)

The dimensions of these keys are fortunately findable in the hive-library that is the internet.

Rummaging in the collection of old-keys, a little key with hollow shaft and an outside diameter of just under 5mm was found. This was then filed/sawed to create the pronged B-Key; the dimensions aren't too critical - the prongs just have to fit in the cut-outs of the latch. The inside diameter of the shaft does need to be large enough to fit around the central stem in the lock of course, so drilled out to 3.2 mm.

Result; a newly minted B-key. 

To remove the cover of e.g. this Burroughs Class 5 calculator then becomes simple. Merely undoing the two thumbscrews at the rear, pulling out the crank, turning the key and lift off.

On the inside of the case-cover, the hooked latch can be seen that is rotated by the key.

And the pin in the base of the machine that is grabbed by the hook.

The Burroughs service department no longer comes round to do maintenance and repairs - so when having an old Burroughs machine this is a very good little key to have, to easily open the machine for maintenance and repairs :-)

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