The Curta.org Bulletin Board

[doberlec]

Dear Curta fans,

I've had the luck to acquire a Curta Type I with a rather low serial number: 11307. It seems to be in an excellent condition. The metal container is a little bit scratched but the machine look as if it hasn't been touched before. Now comes the part which is of my concern: When I use the crank and spin a full rotation the crank doesn't move through the whole rotation in a smooth way. It goes very smooth the first 90 degrees and then the crank is a little bit harder to turn. It is at the exact location, where the rotation counter is getting moved and increased by one. Afterwards the rotation is smooth again.

I didn't have a Curta before so is more resistance on this section of the rotation completely normal? Could it be that my Curta is indeed only a collectors piece and wasn't used before and needs some exercise until all the parts are a little bit worn out? I also noticed that the resistance is mounting when I'm calculating especially when I'm substracting. Is that normal behaviour? Perhaps some of you who own a Curta can shed some light on those issues for me. Thanks in advance

[stenella]

Hi doberlec,

Worry not, this is completely normal. The force to move the rotation counters has to come form somewhere, and it's you who is delivering it. If you move the input register to a number instead of all zeroes, you will find you can feel every single slider as a slight resistance against turning the crank - and the higher the number you set, the larger the resistance ! Have fun with your new machine !

Cris

[doberlec]

Hi stenella, thanks for your answer, that is great news When I saw the videos online from someone operating a curta, it seemed that resistance isn't building up at all, but that is perhaps only because he already could operate it very well. My fear of breaking anything is gone, and I will keep it purring for the spirit of its inventor