More Slide Rule Stories!

In the mid-to-late 50s, the slide rule was the calculator of choice at Tech. Although a small computer found its way into the Math Department at the end of the decade, slide rules were the computer used by “Toots” and carried in a leather case clipped to your belt all day. Except when in one of Dr. McMillan’s math courses, at which time your slide rule was safely hidden in the bottom of your book bag. Math, you see, is a precise science and no estimating contraption was permitted in the good Doctor’s classes within his vision range. But, even when using 5 or 7 place log/trig tables for high accuracy calculations, the slide rule was a quick way to get an “approximate” answer to check your result. Unfortunately for the Doctor’s math classes, slide rule answer checking could only be used for homework.

My slide rule is made of bamboo – a exceptionally stable wood, very smooth sliding and a lot more elegant than the metal versions. I still have mine and after 60 years, I think I can operate most of the functions.

Pete Rankin ’59EE

I used a slide rule my freshman year at Tech. Sometime early in the fall quarter (1974) of my sophomore year I bought an HP 45. The price had recently dropped about $100 and it was only $325 or so. We were married that summer and my wife commented the day I purchased the calculator was the first night we didn’t go to bed together. I stayed up late with the calculator!

John R. Wiltse BSEE ’77

Yes indeed. Last time I laid eyes on it – sitting comfortably in the storage garage at my Portage Entry summer residence south of Chassell, alongside A Dana’s Handbook of Mineralogy and my old hand lens from Kiril Spiroff’s mineralogy class.

Dan Koss ’59

When I started at Michigan Tech in the fall of 1964 I had a Pickett metal slide rule with 33 scales and was a yellow-green color, taunted to be better to view than the white bamboo type. This slide rule was a gift from an aunt. No, I do not have it nor do I have my old book bag. Like all other engineering students at the time I had to take chemistry from Doc. Barry. His favorite way of arranging his multiple choice (guess) answers would be something like this:

  1. A) 0.167
  2. B) 1.67
  3. C) 16.7
  4. D) 17.3

Accordingly, you had to be efficient at scientific notation and moving the decimal point around, which I wasn’t. He should have been taken behind the woodshed and flogged. But he was a full professor and I was just a poor slob “student.”

Larry Joy

BSEE May ’77 (should have been ’68)


One response to “More Slide Rule Stories!

  1. I too have a slide rule (a Post Versalog bamboo unit), which I still use occasionally. I used it for a lot of calculations, especially trig and compound interest. When electronic calculators came in in the mid-70’s, I switched to HP desk and hand units, which were even more versatile.
    Speaking of bygone calculators, does anyone remember the Marchant manual desk calculators that were used in the mid-60’s for surveying calculations, which required reading and interpolating log tables for precision?

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