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Bunzel Delton 5

This machine came to me from an old office machine salesman, who had worked for Marchant in the 1960s, and back then had spotted this calculator in the shop window of an antiques shop - and obviously, being professionally interested in mechanical calculators, he bought it as a decorative piece.

Fast forward about 50 years, and it was now time to downsize, in order to move to a smaller home. The gentleman in question sent me these pictures: Bunzel calculator picture 1

Bunzel calculator picture 1

Bunzel calculator picture 1

Bunzel calculator picture 1

Bunzel calculator picture 1

Bunzel calculator picture 1

Bunzel calculator picture 1

Bunzel calculator picture 1

Bunzel calculator picture 1

Bunzel calculator picture 1

So then - a typical Bunzel-Delton machine, model 5, only a few numbers away from my own (n 5261, vs. n 5202 for mine), year of construction 1905. In all other respects, the machines are identical. Since the owner did not live that far away, and was interested to come and see the collection, I offered to clean and polish the machine, and then sell it on for him.

Some things needed attention - the nickel work needed polishing, as did the wood, especially the lid, where the shellac varnish had been taken off for some reason, and the mechanism needed cleaning and lubrication. In addition, there was no key to the lock, and when I found a key, the lock didn't work. When the box was picked up, the bottom fell open - the lock pin at the back for keeping the stand closed had also disappeared.

I started by disassembling the machine for cleaning and lubrication:

Bunzel calculator picture 1

(before you panic, there's an M2.5 nut in those vice grips to screw these studs into ...)

Bunzel calculator picture 1

Before and after:

Bunzel calculator picture 1

Bunzel calculator picture 1

Reassembly of the sliders:

Bunzel calculator picture 1

Bunzel calculator picture 1

The lock ...

Bunzel calculator picture 1

Bunzel calculator picture 1

...with broken spring. A quick silver soldering job later, this was as good as new.

And so this is what it looks like after cleaning:

Bunzel calculator picture 1

Bunzel calculator picture 1

Bunzel calculator picture 1

Bunzel calculator picture 1

Bunzel calculator picture 1

To round off the restoration, a replica instruction sheet was glued to the inside of the lid - all done!

Bunzel calculator picture 1