Layers of history - 'excavating' a crusty Comptometer model F

A not-expensive local pick-up - it didn't look so bad in the pictures (dark, bad lighting). When seeing it at pick-up I did consider leaving it - it was not only rather dirty, but extremely rusty (crusty) and a whopping big iron carrying handle was mounted on the back.

But it was a century-old model F and did look a right 'project', so the sale went through and yet another Comptometer taken on. (Have been quietly acquiring more of these; fascinating machines.)

A solid steel handle riveted to the rear panel. That is not original.

Not subtle, that handle - though it actually is a good idea. It makes it so much easier to pick-up and transport the machine. Even the standing on its front panel isn't too much of a problem, it's fairly stable. This definitely is something that the Felt & Tarrant company could have done themselves (though perhaps not on the rear-panel or quite this crudely).

This Comptometer was handed down from the seller's grandfather, who'd worked with it at Smit, Slikkerveer - that was (is) a large industrial/electrical company founded in the 1880s. Smit was absorbed in Heemaf in '63 and after several corporate moves the Smit activities are now part of Alstom and produce electric-drive for trains. This Comptometer was made around 1918 and likely used for decades at Smit. It probably got its handle added when it was no longer 'new', but still actively used by perhaps a 'roaming' operator. And then taken home at retirement, to be kept as a memento. When it passed to the next generation it ended up in a damp shed. That's when it will have developed its 'patina' - especially the key-stems became very badly rusted. 

When cleaning out the shed of the father, the grandfather's old machine was put up for sale - there might be someone that'd still want it.  There was :)

After getting it home, it was first stored in the garage (much too dirty for taking indoors), before taking it out for a proper cleaning and repair over a a few days - an 'excavation' almost. 

There are minor differences between the models, but all 'shoebox' Comptometers can be taken out of the casing pretty much the same way. This gives access to the mechanism for a cleaning - this one was dusty even on the inside. The empty casing can then safely be given a good wash.

Fortunately the mechanism itself didn't need taking apart much (intimidating, quite beyond me). With liberal amounts of a light machine oil (sewing machine oil) and working the various parts, the whole mechanism slowly came to life again. At first a bit slow with 'sticky' carries, but after a while the full ripple carry from 099999999 to 100000000 again zips through the machine. Everything works and no broken or bent internal bits!

With the top-plate off, this also could be thoroughly scrubbed. One thing I'd not noticed before on Comptometers was that the key-stems had a gasket; every stem-slot had a fibre or card sleeve to act as an oil-soaked gasket. These were hard with old oil and/or crumbling and were all removed.

Considered replacing these with new, but did not want to risk one of these gaskets coming unstuck and then getting lost inside the mechanism. With the light use this machine will see, it should be fine without these oiling-gaskets. (Would the fact these gaskets were still present suggest this specimen hadn't ever had its top-plate removed for a full-overhaul maintenance?)

Another layer of its history were marks from a divider placed between column 2 and 3 (cents and guilders) and between row 5 and 6. The copper looks scratched/worn away by a divider, down to the plain steel. 

The horizontal mark suggests a divider to help practice/use the touch-method. Experienced (and fast) comptometrists only used the 1 to 5 keys in every column. All numbers were entered by touch without having to move the hand, never taking the eyes off the figures to be added made this a very fast method.

It was also revealed that the greasy dirt-layer between the keys had actually been protecting the copper finish of the machine - still closer to the original colour than the rest. The darkening of the 'clean' surfaces is probably due to decay of the clear lacquer and oxidation of the copper underneath.

Even though it was part of the machine's history, the rusty handle on the back was removed. The holes left by the 1/4" rivets (!) were plugged and made less obvious with copper-colour paint. The lighter, original colour where the handle had been also confirmed that the darkening (and rust) was probably from its time in the shed.

The patent dates again all readable, from the original 1887 to the most recent 1914 date for a model F.

All the stems were scrubbed clean with steelwool and the cellulose-nitrate keys were washed with soap and water. Kept in sets per column, to place them all back in their original spot. Bent stems (several!) all carefully straightened.

The case was cleaned with soapy water and 'crusty' areas were polished down to a smooth rust-finish. The case now has multiple shades of brown in interesting patterns that would be the envy of some modern 'industrial-look' decorative items. Sealed with a waxing, safe to touch and handle.

With clean keys and remarkably shiny key-stems, it all looks much better :)

The re-mounted, clean keys confirm that this machine was used by an experienced operator - the lower half of the keyboard is worn. This shows it was used mainly for addition of amounts up to 4 or 5 digits large using only the lower half of the keyboard with the right hand - fingers resting on the 3-keys, as per recommended method.

The machine was completed by re-fitting a red correction-key; again a proper well-used Comptometer model F. 

The model F was introduced in 1915 with a white Correction Button for re-setting the controlled-key mechanism and blank decimal-markers. Numbered-markers were available sometime before mid 1917 and the correction button had already changed to red before that. With serial number 135855 this Comptometer was probably made in 1918 so will have had numbered decimal-markers and a red key from new.

It was actually surprising how well this machine could be recovered back from its extremely rusty 'boat-anchor' condition. A nice (and cheap) addition to my modest collection of Comptometers :-)

With occasional 'exercise' this Comptometer should remain in good working order for decades to come as a 'collector-item' or historical technology-artefact; a new layer being added to its accumulated history.