Monday, September 4, 2023

Refurbished Comptometer model H

This Comptometer model H got refurbished, again, in 2023 :)

The old, drab paint from a late 1930ies or 1940ies re-build was stripped from the panels.

The top-panels were re-painted in a matching brown copper-colour.

New keys were manufactured.

The new keys were fitted to cleaned key-stems.

The decimal-markers riveted back on the front display-cover.

The top-cover place back onto the mechanism and keys re-mounted.

New window and feet improvised and fitted.

And then the whole machine is put together again, clean and cosmetically very acceptable.

However, the column 6  had been malfunctioning - caused by sticky old lubricant. Closely watching what was going wrong to identify the cause (peering into the mechanism, operate machine, use flash-light). Then some prodding with a wooden skewer to get suspect parts unstuck. This fortunately confirmed that old grease was the cause. Hopefully with frequent exercise the problem will be solved, exercise is anyways important for all mechanical calculators. (Am not confident to take a Comptometer mechanism fully apart to get at the levers inside the 6th column!)

The view from the side gives a pretty good indication of the density of levers, rods and springs throughout the whole machine. It is amazing in its complexity, very clever - mechanically rather marvellous :-)

For example the holes-pattern in the intermediate gear in the register (only a small section visible) is functional (less mass, more speed) - it also is a mechanical detail that's just very nice to see.

This particular model H had been bought (cheaply) in a rather bad condition. On the (bad lighting) images of the listing it had looked fine, but seeing it in daylight after picking it up its drab finish was clear.  That, with  its decaying J-model plastic-keys were evidence that this was older rebuild.

It probably was rebuilt and re-sold already in the late '30s or 1940s. The calculator itself has serial number 209,945 and dates from around 1921. These were expensive office-machines (entry-model was about twice the price of a large standard typewriter). There was a market for rebuilt Comptometers, both by the manufacturer and third-parties. Rebuilding was especially common in the immediate post-war period, but also happened in the 1930s - the F&T company even advertised that they would not guarantee rebuilds by others.

The internal mechanism of this specimen had luckily survived quite well; almost no rust and clean with relatively little gummed-up old lubricant. Overall, Comptometers are amazingly durable - especially considering their complexity and the amount of fine-adjustments in the mechanism. 

So, after the initial disappointment of buying a badly-ageing rebuild machine; now it's a shiny clean Comptometer model H that calculates just fine. Perhaps almost as clean and as fast as it was back in 1921 :-)

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