Imported from St. Petersburg to Rotterdam, an Original-Odhner arithmometer model Ag

Imported from St. Petersburg, Russia to Rotterdam, Holland around 1908 by the J.A. Ruys trading company,

The Ruys trading company was the continuation of the Voorhoeve trading company, renamed in 1904 when J.A. Ruys bought-in to take over the company. A major line of business at that time was the importing and sale of Hammond typewriters, and Odhner calculators as shown in the 1904 newspaper ad below.

Hammond machines in The Netherlands often have the brass Ruys shield in the same style as the Hammond shield on the wooden base.

Ruys also advertised the Odhner calculator by itself, for example in this newspaper ad from October 1907.

(More advertisements and some background on Odhner at the informative mechanical calculators pages of Jaap Scherphuis.)

The St. Petersburg-made Odhner machines really are the original pinwheel calculator, the start of the 'category'. As such, it is a historical milestone-machine for automated calculation When this one showed up on the local classifieds site, curiosity won-out and I made an 'impulse purchase' - pretty much the item as advertised in that 1907 newspaper ad.

With almost 30,000 made, these calculators should not be rare and be available at relatively modest prices. The very early ones (with short crank) are however eye-wateringly expensive these days and even the later, nice specimens with case are becoming sought-after. This later specimen in the state it was in, was fortunately affordable.

This is a model A with 13 digits capacity in the result register. An extra 'g' indicates a bell, so this is a model Ag. The marking with 'Original-Odhner' instead of 'Odhner-Arithmometer' started in 1907 (to set it apart from the increasingly successful clones). Going by the serial-number of 14618 and the advanced features (comma-sliders, fast-clearing bar) this machine was probably made in 1908 or perhaps late '07.

It had been given as a present (retirement gift?) to the grandparents of the seller. Nothing however was remembered about the background or the occasion, it had just been 'around' for decades. There was no case and it is mounted on a (1950s?) small multiplex board. And now sold.

The calculator was also missing its bell, several screws and generally rusty and dusty. It was also very stiff - so did not try to operate it before cleaning and lubricating. Otherwise there is risk of blocking the machine or even breaking something from excess stress.

Without taking apart any of the more complex sub-assemblies, like the drum or registers, it was laid out in its main components. All mechanisms were oiled (sewing-machine oil) and gently worked free. Some assemblies may have to be taken apart later for more thorough cleaning and removing excess (and old) oil.

Metric M2.5 was a good fit for replacements for the cover-screws. Heads were modified to match the pattern of the remaining original screws ('instrument-head'). 

Unsure what screw-threads were standard in pre-revolution Russia, but when the Odhner production-design was made in 1890 or so it was probably designed around 'Sellers' or American threads. The cover-screws are what today'd be called UNF #3-56 screws - the M2.5 is nearly identical in diameter, pitch and has the same 60 degree thread-angle. (International metric is derived from French standard screws, that are in turn derived from William Sellers' American screws with 60 degreed angle.) 

Assuming old American-size threads, the screws in the register wing-nut flange are probably #5. Anyhow, a decent replacement for a missing screw was scavenged from a 1947 Underwood standard.

Most notable of course was the missing bell - a small bicycle bell! At 32 mm diameter it is slightly too large, but does fit and at overflow makes a wonderfully bright 'Dingg!'. It being black also is in keeping with the machine's overall 'not shiny' appearance :)

On older Odhner machines without bell, the carriage can simply be slid out. On this model however, a locking screw has to be removed first (and the bell taken off too). This screw is accessible by first removing the back-panel - it has a squared-off head that will also prevent it working loose as it strikes the two end-stops.

On the right in the image above the only safety interlock of the machine can also be seen. The steel disk with one cut-out works in tandem with the slotted bar to prevent carriage and drum being operated at the same time.

The machine is now free from the copious dust and dirt. The mechanism is mostly functional, although not yet as it should be in all positions. Some of the register-wheels hardly want to move - more disassembly and cleaning will be needed for that. There is also the chance that it is just worn-out. 

Additionally, some of the gear-train and handle have developed play and cause the timing to go slightly off for the safety interlock - to be looked at later too. The rusty covers could perhaps be re-finished, but it may all be left as it is. The calculator just looks its age :)

It also definitely looks 'old' when compared to a 1930s Odhner, side by side in the above image. The later, Swedish-built machine is smaller than the older Russian-made machine, yet with many more features and safety interlocks. The size of the old machine, its features and also very much the curly script do evoke the turn of the century (the 20th century, that is).

A survivor from the dawn of widespread mechanical calculation :-)