Tag Archives: slide rule

Thacher’s Slide Rule — Thirty Feet of Numbers!

The slide rule shown on my home page is mine.  It is true that I broke it by not packing it properly for shipment in its later years, but I will never throw it away.  Here is a picture showing the crack.

midsize-Moon-SR-3

It was my first slide rule.  It cost around $20, which was a fortune to me as a starting freshman at Stevens Institute of Technology, but for a kid who had a predilection  for numbers, it was a marvel.  And it went on to help design a lot of great stuff, not the least of which was the Apollo Back Pack.  It couldn’t spit out 50 decimal places, only three at most.

But there was Thacher.  My slide rule is only a foot long.  His was 30 feet long — no way to hang that from your belt!  And now I own one.  Of course it’s too late.  I’m retired.

IMG_2384

It has a slide as you can see and many progressive scales that make up the thirty feet.  I won’t bore you with the details of its history.  You can find out all you want by looking on web, for instance:

http://americanhistory.si.edu/collections/search/object/nmah_1131290

The one thing my original slide rule and the Thacher I own have in common.  They were made by the same manufacturer, K&E.