Olympia RT4

One of the very last pinwheel calculators, bar none (1969!), in the same league as the Facit 1004, Brunsviga 16T and Schubert E. Whereas the Facit CM 2-16 or 1004 was timely (end of the 1950's), and it was sold a lot and can be found often in collections, the story is a bit different for the other two. The Schubert E was built in a very limited number from 1961 on, sales starting in 1963. It flopped completely. Imagine the insanity of bringing a new handcranked pinwheel calculator on the market as late as 1969! About 1500 were produced until 1972 as a cheap alternative for the newfangled electronic calculator, when realisation had not entirely set in that the mechanical era was actually very much over already. The machine sports all of the controls on the right, for easy one-hand operation.

I appear to have had three of these machines - n 1276, which was a bit finicky to get and keep working, n 3644, as well as n 1244, which I am very happy to have found here in Belgium. N1276 was sold in Antwerp by Frans Jacobs & Zoon. It came to me completely blocked. Since the machine conforms to the "new thinking" in machine construction, pretty much nothing can be disassembled, as it is all peened or twisted together and cannot be taken apart without destroying it. I had to satisfy myself with thoroughly lubricating all of the insides with a thin silicone oil and trying to push and pull here and there until everything clicked in place. Two very frustrating evenings indeed! The return spring for the pinwheel cylinder seems to have lost its strength, so it is very difficult to get the machine really back to zero - the leftmost digit in the multiplier can almost never be used when the housing is in place, so the machine will either not indicate the number of turns after a reset, or, if the pinwheel cylinder is shifted left and right a few times, the counter wheel one place to the left will show the multiplier. Other than that, the machine is stiff, but it works. Of the other two that I have, one is very prone to blocking and this has to do with a slightly deformed plastic numeral gear in the counter register in position 2, but the last (latest) machine appears to work without issues, including the back transfer. That operation definitely comes with a manual though ... The way to operate it is as follows - you can do back transfer from either the result or the counter register. In both cases you have to zero the setting register first by pulling handle I all the way forward - this will slide the setting register into its starting position. Now for backtransfer from the counter, you push the backtransfer button, pull lever I forward until it stops, release, and then clear the counter. If you now press the 10 button, the setting register slides into view, and the number that was originally in the counter is now in the rightmost part of the setting register. If you need it elsewhere in the setting register (e.g. on the left), you can crank the machine once to add it to the result register, and then transfer it back from there in the correct position. This works in the same way - clear the setting register by pulling I, then press the "10" button. The setting register shifts 10 places to the left, and you can now set it where you would like by carefully pulling I towards you to shift it to the right place by place. Stop when it is in the position you want, and release lever I. Now press the back transfer button, pull I to the stop and release, then clear the result, and the number there will transfer to the setting register.

Some pictures of this very rare and special machine: