"John Grossbohlin" wrote in message
m...

"Han" wrote in message
...
"Martin H. Eastburn" wrote in
news:ZjW6l.88147
:

Talking about abacus ? I bet the third from the bottom on this page :
http://www.vintagecalculators.com/ht...lculators.html

Kingson Four-Rule

Martin

My Dad had one like that, but it got lost

I had one like that when I was a kid. I think it was the Exactus model
shown on the web site... the instruction manual looks familiar to me! I
still have a circular slide rule with the case and instructions... I got
the slide rule just as the TI pocket calculators were starting to drop
from the $400-500 range to about $100 in the early to mid-70s. I figured
the slide rule would be a neat relic. Wish I'd realized that about the
Additor type calculator. ;~)

http://www.vintagecalculators.com/html/exactus.html

I can recall how carefully you had to stick the stylus in the little
notches and move them... To get accurate results you really had to pay
attention and have a feel for the tool, much like using my hand tools vs.
running things over my jointer or through my planer. ;~)

John


John,
Lots of them still available on eBay - enter
mechanical calculator
in the search box, and the bottom of the page will show several Addiator
type devices in the eBay stores section, as well as a couple in the auction
section.
Kerry