Solo Handy Adding Machine
The Solo Handy Adding Machine was made in Japan in the late 1960s, early 1970s. It is unclear who the manufacturer was. In the United States it was also rebranded as the Chadwick Mini-Calculator, in Germany it was rebranded as the Neckermann Haushaltkalkulator, but in the UK it seems to have only been sold as the Solo Adding Machine.
It has 7 coaxial wheels that you can move with your finger, very similar to the Högfors for example, except that its carry mechanism does not used stored energy. When a carry is performed as you move a wheel, you have to exert more force to the wheel. If several carries are performed simultaneously, e.g. from 99999 to 100000 it can be very hard to perform the calculation.
As the carry mechanism is so simple, subtraction can be performed by moving the wheels in the opposite direction.
Unfortunately the plastic casing is glued shut so it is not possible to open it and show the mechanism.
In Germany this calculator was rebranded as the Neckermann Haushaltkalkulator. The only difference between the Chadwick and the Neckermann other than the label on the front is that the clearing lever has a different colour.
Below is a video I made that demonstrates the Chadwick and Neckermann calculators.
Here are some advertisements from online newspaper archives.
Rechnerlexikon has a page for the
Solo Handy Adding Machine.
Rechenmaschinen Illustrated has an entry of the Neckermann with pictures.
Thomas Kirchhof has a Neckermann in his collection.
Retro Calculators has a Chadwick Mini-Calculator, Neckermann and Solo.
Museum of Applied Arts & Sciences has a Solo.
John Wolff has a Solo Handy Calculator.
Chris Staecker's YouTube channel has a video about the Chadwick.
© Copyright 2020 Jaap Scherphuis, mechcalc a t jaapsch d o t net.