Carriage cleaning of the Burroughs Portable adding machine

This Burroughs Portable adding machine has the wide carriage option; a 12 and a quarter Inch carriage with tabulator stops.

The brightwork on this wide carriage was very dirty and/or corroded. Most of the brightwork originally would've been shiny nickel-plated, but now with the dirt of decades and some spot-corrosion:-no longer very bright. One of the tabs below cleaned back to a shine proved it was mostly dirt.

This wide carriage of the Burroughs turned out to be not so easy to take apart for cleaning. Several collars are pinned onto their rods and even the platen-rod has a ratchet-wheel doweled in-place. Taper-pins are very hard to remove. So for now only limited cleaning of the most exposed (and reachable) parts. Removing side-plate mounting screws allowed the side-plates to be shifted just enough for the tabulator rack to come off.

As can be seen in the image below, the main spacer-rod behind the paper-tray was not removed and still has a brownish hue. However, the tabulator bars and springs did come out quite nice. (And no longer look like you'd catch something off them at five feet.)

One detail when re-assembling the carriage is the positioning of the ratchets. The Burroughs has two; a driving ratchet wheel and a holding ratchet wheel on the platen rod - both visible right next to each other in below image. The holding ratchet wheel is fixed in position on the platen rod by a screw.

This holding ratchet wheel must be adjusted so that in the holding rest-position the driving pawl on the driving ratchet-wheel is only-just released and drops free again after a line-feed.

This was the cause of the carriage line-feeding issues of the machine. It would only do a line-feed when set to dual-spacing and block the platen from reversing using the knobs. That was because the pawl could not drop free, but was kept under pressure (and failing to fully advance the platen). Very likely this was not adjusted at the machine's last servicing - perhaps in the 1960s still. After assembly it was set to dual-spacing and the carriage did feed, so no more attention given.

During cleaning; one little artefact of the manufacturing process of screws; the slots of screws were cut. On this one screw (right), the slotting-machine must have been set a little too low, neatly splitting the entire head.

Cleaned and carefully tightened back in place. The split head makes it a weak screw, but it held the paper-roll bracket on for 97 years and should do so for another 97 years.