The window sheet may well be original, although this Comptometer clearly was serviced and repaired in the past. So it may be a replacement, but probably done by a (the) company servicing - perhaps in the 1930s using a Model J part? Maybe the spare-parts lists, drawings or Bill of Materials of a Comptometer will turn up in the future.
The snippets from a repair manual of 1919 on Brooke Boering's site confirm that Felt & Tarrant used three-digit numbers, some with a letter pre-fix. For example on a Model H the subtraction (cut off) lever is part T604, a toggle pivot link shaft is part 865. Perhaps we can now add that the curved celluloid sheet is part J281.
The Model E was a much more complicated machine than its predecessor C. With this model Felt and Tarrant added error-detection and control mechanisms that not only increased cost, but also made it relatively fragile. (These new feauters would likely have been considered essential by the company in their fighting off the direct competition of the Burroughs Calculator that launched 1912.)
The Model E machine's frame is noticeable thinner than the preceding Model C, comparitively flimsy. The keystems with the many corners (stress concentration at bending) and narrow sections are vulnerable too. This specimen indeed had a broken key-stem and the top plate had lifted from the holding brackets at the front. This distorts the case and can jam the cut off levers.
Even though from the classifieds ad it was clear it was blocked, had a broken keystem and was rough (and dirty!), it also was 25 Euro and a Model E: so did a pick-up of the machine. Model E's are not all that common, that likely is because the E is not as robust as other Comptometers - it is rather fragile, in fact. Even though thousands were made (7700?), the survival rate of the E is expected to be much lower than that of e.g. a C or an F model.
To clean and repair, the usual steps for a Comptometer; the mechanism was taken out, all keystems removed and everything was cleaned. Taking out all keys enables cleaning also of the top plate in the key-area, often has the accumulated dirt of many decades. The Model E key-stems can only really be cleaned when out of the machine.
The broken 9-stem was given a 'fix'. It really should be hard-soldered or brazed, but not (yet) having the tools for that it was first soldered. To compensate a bit for the soft joint and anycase to mitigate the butt-joint a splint was added. Slots were sawed in both ends and a sliver of iron inserted. (The lower end of the broken keystem was initially thought to be missing - simply could not be found in the case or in mechanism around column 9 - only when re-inserting column 6 did this bit drop out with a tinkle. Lucky!)
The soldered joint then sanded smooth and the key can be fitted back into the machine. This weak keystem not placed in its original corner position of column 8, but swapped with the intact stem of column 7.
This joint is too soft really, but should hold for a few years until a proper hard-soldered (or welded) repair can be considered.
Again complete and fully functioning - when taking care to operate gently. Re-assembly also needed care, the order of tightening of screws of the case making a difference between columns being blocked and everything working as it should! Another confirmation that the Model E is a fragile machine - at least this specimen.
This particular machine was maybe one of the last to be exported from the US to Holland, before shipping became dangerous and expensive. The nameplate is the factory 'generic' in English without any patents.
The rear of the case lists the patents, from the first 1887 to an October 1913 patent.
This Comptometer was used - judging by the wear it was used heavily. The rust on the sides shows where hands have rubbed off the protective lacquer and even the copper coating to expose the steel. The machine was also serviced and repaired in the past. Several replacement screws in the case show it was taken apart completely at least once. The broken keystem had solder remnants; so when that initially broke the machine was still valuable enough to try a repair to keep it in use.
The new Controlled Key Comptometer Model E - repaired! (And fragile.)
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