I am interested in purchasing old mechanical calculators and other scientific devices. I also collect wooden and metal engineering slide rules that are in very good or excellent condition. In addition, I am interested in other mechanical math and science devices such as planimeters (mechanical integrators) and cipher (encryption/decryption) machines.
I am interested in any type of mechanical calculator, but I am especially seeking the "rotary" calculators that were made by Monroe, Friden, Marchant and other manufacturers from the period of the 1900's through the late 1960's. I am interested in both electrical and non-electrical mechanical calculators of both the desk and hand-held models. I am especially interested in hand-held Curta brand calculators.
I am not interested in adding machines that print on tape or electronic calculators. However, I do collect non-printing adding machines such as Comptometers.
If you have an old calculator, slide rule, or other interesting mechanical device collecting dust in a closet, please send me an e-mail message.