Friday, June 14, 2024

Remington Portable adding machine on its feet again

The rubber feet of 1930s Remington Portable adding machines are nearly always 'gone'. That is - they will be present, but invariably are hardened and/or completely squashed. As in this wreck-machine below:

As a finishing step of reviving this machine, the gone-to-goo old feet were broken off the machine. A hole may need to be pried in the centre of a foot to get at the mounting screw. When removed, the foot-remnants should be completely broken apart to retrieve the washer. (This washer would originally have been moulded into the rubber foot.)

New feet that are a decent-enough fit were modeled in CAD. In this case, printed in regular 'plastic' and not in rubber. The conical washer is needed as insert - designing the foot with separate washer makes it possible to print on an FDM 3D-printer. It's not a difficult or critical part, any printer should be able to create this fine - STL-files available for download here.

The tapering top of the foot is needed to clear the various pins and screw-heads that poke through the base into the foot-pocket of the machine-base. The pocket allows mounting the feet with the original, salvaged screws and washer.

Original feet had a circular 'tread' - as shown below. This pattern would actually be fairly easy to create with 3D-printed feet in rubber, but in this case settled for basic, hard feet to be soled with felt (or alternatively, a pad cut from self-adhesive rubber sheet).

The printed feet here finished with a 'sole' from furniture-pad felt, great for sound-dampening. Adding some latex-glue to the felt made the feet grippy. Had grey felt, so blackened the sides.

The Dalton adding machine thus on its feet again and fully functional.

These 1930s Brennan-type Remington Rand adding machines are pretty common today on the usual auction and classified sites. They can only really add numbers (which they do very well and they print a list too). Perhaps not very exciting machines and indeed they are not very valuable today. 

Still, if you can find a decent-looking and complete specimen: they are brilliant late-1920s digital-technology and can basically last forever.

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