Needs Fixing

I am frantically busy today, trying to absorb the last few facts from my cell biology course, before completing and submitting my course assignment. In consequence I was not particularly delighted when I came across this modern calculator (perhaps not quite that modern) from my collection which has now developed a fault. In general I have collected together a few old mechanical devices like this, which had been broken and which I have repaired; simply to preserve them for posterity. This one was working, but it now refuses to reset its multiplicative register on the left-hand side. It is probably nothing more than dirt or a small part that has jammed and needs freeing, but it still requires a complete strip down of the carriage, which is a bit more complicated than taking the average clock apart. It will have to wait until after my assignment is submitted, but I find that I would much rather sort this out now than complete my assignment! However, looking at it sitting waiting for me to do something with it, I realised it might make a reasonable blip.

This particular machine is a rather ancient Swedish Odhner, which will add, subtract, multiply and divide. They are rather like the old mechanical typewriter being composed of very solid metal parts and very seldom going wrong. However, the last one of these which I did repair required me to make a gear wheel as one tooth had broken off of its existing wheel. I used one of these in anger back in the early sixties (I had already worked on my first digital computer before this), for doing calculations where more than six figure accuracy was required and became rather attached to them. Prior to World War Two and for a few years afterwards, machines like this were used for almost all engineering calculations that required a significant degree of accuracy and were in fact in use on the Manhattan Project which produced the first atomic bomb. In consequence when businesses started throwing them out I managed to acquire two or three broken machines of different manufacture and restore them to working order. Over the years I have collected many bits of junk interesting devices.