Musings on a Slide Rule

[DWalt]

When I was in engineering college (Ohio State), the Big 3 slide rule brands were K&E, Pickett, and Post. Picketts were made of metal, an aluminum alloy I think. I didn't like them, I preferred the K&E. They came in several lengths, 10" was the most common. There were also 5" (pocket size) and 20" when more precise results were needed. In my first job, we had one 20" slide rule in the engineering office in case anyone required more precision. It was seldom used. There were also circular slide rules. I never liked them either but some did. There are a great many slide rules which have been made for specialized applications, such as navigation. I once had a slide rule which was used to calculate load weight distribution in DC-3 cargo aircraft. When I was teaching Freshman engineering drawing, I taught basic slide rule use as part of that course. That was back when people were still using pencils, triangles, and T-squares to draw. That has also been computerized.

As someone mentioned earlier, slide rules are not completely dead. I carry a 5" K&E log-log duplex decitrig in my truck glove box for calculating gas mileage. Surprisingly, I still remember how to use all of the functions, but I presently have little need for that skill. But if I am ever stranded somewhere in my truck and need to find the cotangent of 53 degrees, the cube root of 313.5, or solve for an unknown side of a triangle, I can sure do it.

 

[jlrhiner]

You'll notice in the background on my desk. I use it to scare the Grandkids.

 

[fishcreekrim]

I graduated from high school in 1976, I took high school chemistry with a slide rule, two years later I took college chemistry with a calculator. A Sharp with scientific notation.

 

[DWalt]

I remember in my college analytical chemistry classes we were required to use 5-place logarithm tables to do calculations. A slide rule was not precise enough. I doubt if few people anywhere today even know what log tables are.

 

[old 1911 fan]

When I was learning to use a slip stick in the early 60s I was given a wooden slide rule from a neighbor. He and his wife were in Nagasaki when we dropped The Bomb. It is one of my prized possessions.

old 1911 fan

 

[Ivan the Butcher]

Before I was born (1956), my Mom was a computer! Mostly she found accounting jobs. But she worked at a couple of aircraft firms. After I was born, she would get temporary jobs with Lazarus' Department Store tallying inventory for tax time.

In 1967 my older brother took her 20" slide rule to school for Algebra II class, the teacher took the rule home to figure it out. We never saw it again! That same school year dad bought our first Olympic electric (NOT ELECTRONIC) calculator. It was a little bigger than an adding machine but had now paper tape! and cost about $500. My 7th grade math teacher didn't believe me when I talked about the 24 digit number screen (Wire frame not LCD) and you could choose zero, 12, or 24 decimal places. We were allowed to use adding machines for homework if we included the tape. In 7th and 8th grade I could do any of those problems in my head. The teacher thought I was using the Olympic and said I was cheating, until I did 10 consecutive problem in my head in front of the class. I wish all of life's problems were that simple! My brother still has problems with addition! (but he can spell) I can do math pretty well (But can't spell worth a hoot!) Yet he made all the money!

Ivan

 

[steelslaver]

The hours I spend learning how to use a slide rule? I now chalk them up to building mental muscle. If you whipped one out around a high school today they would think you lived in a cave.

 

[CH4]

Never had to use a slide rule, but the professors used them and were usually faster than those of us with calculators. I had a TI-55, the instruction manual was 3/4 of an inch thick. I always wondered if learning how to use the slide rule would have been easier.

 

[Engineer1911]

High school graduate in 1966, I feel older than dirt. I definitely don't want to type about my Post VersiTrig slide rule. I remember doing math calculations with 4 place logarithms, but don't remember if it was math or physics class.

I graduated from high school without Chemistry, took Physics, and mercifully only had to take first semester chemistry in college. Great class -- 250 students in the lecture hall and 245 were first semester female nursing students and 5 "old guys" starting engineering on the GI Bill. 1974 / 1975 was a great school year!

Bought my first Unisonic calculator at K-Mart for $23.95 in October 1974 ($123 today).

EDIT: Years ago, I sold three Post slide rules, the big (not positive about the names) VersiLog, VersiTrig, and a shirt pocket 5". The VersiLog was about 2" wide and had scales on both sides and VersiTrig was the student's model 1-1/2" wide. All three were made from bamboo with laminated plastic faces.

 

[WardenRoss]

...But if I am ever stranded somewhere in my truck and need to find the cotangent of 53 degrees, the cube root of 313.5, or solve for an unknown side of a triangle, I can sure do it.

Yea, that's a thought. I may need to figure the resonant frequency of something. Isn't it the inverse of 2 pie times the square root of the inductance times the capacitance?

 

[S&WsRsweet]

Congratulations on a great find and an even greater price wow 5 bucks ! Also congratulations on having what sounds like a fine son .My dad was born into poverty and he did pretty well for himself and our family and close to the end of his life one of my cousins during a family get together asked him how he would define a successful man .He said if you raise your children today where they can stand on their own and make a good living you have been successful .Sound like you are a successful man .

 

[Gaffer]

Another thing about slide rule use is that need for the "power of 10" as an aid. Supposedly using the Slide rule and the Power of ten you can work out calculations to 3 decimal points. I got extremely proficient with math at tech school and graduated with top honors after getting failing grades the 1st semester. Spent 32 years with Ma Bell after that and never had to use a slide rule again.

 

[DWalt]

"Before I was born (1956), my Mom was a computer!"
For centuries before IBM existed, there were people (called "computers") whose job it was to perform mathematical calculations for business, engineering, and scientific purposes. Most of them were women.

 

[427mach1]

"Before I was born (1956), my Mom was a computer!"
For centuries before IBM existed, there were people (called "computers") whose job it was to perform mathematical calculations for business, engineering, and scientific purposes. Most of them were women.

Watch the movie Hidden Figures if you want to see some human computers. I got to help during the filming of all the wind tunnel scenes for that movie; decided I won't give up my day job.

When I was a young engineer, we needed to measure the area of an irregular shape on a drawing. One of the lead engineers was rumored to own a planimeter so we asked him if we could borrow it. He reluctantly loaned it to us and told us to be very careful. Opening the box, we discovered the markings, "Property of Vega Aircraft Corp", which was subsidiary of Lockheed from about 1937 - 1943.

 

[ParadiseRoad]

...I bought a slide rule when I was in high school...

...my Dad taught me how to use it...the only Dad in my group of friends that could...

...it's still around here somewhere...I need to find it and get it in our antique display case...

 

[Pop's2]

I still have at least one slide rule tucked away in a drawer somewhere.

In college (1958) took a course in celestial navigation where the professor made us do our calculations longhand and then introduced us to Naval Almanacs and nomographs.

To day I have trouble deciphering "Smith" charts when comparing radio antenna designs.

 

[Onomea]

Congratulations on a great find and an even greater price wow 5 bucks ! Also congratulations on having what sounds like a fine son .My dad was born into poverty and he did pretty well for himself and our family and close to the end of his life one of my cousins during a family get together asked him how he would define a successful man .He said if you raise your children today where they can stand on their own and make a good living you have been successful .Sound like you are a successful man .

I appreciate the kind words very much, S&WsRsweet. Ultimately, for most of us anyway, all we really leave behind as our legacy is our children. My life has had its ups and downs, but my three sons, well, they have made it all worthwhile.

 

[ameridaddy]

I wish I still had my high school K&E. It looked just like the OP's piece. In college in the early '60's, I "upgraded" to an all-aluminum Pickett log-log-desi-trig, which I still have. It never was as slick moving as the old K&E, tending to gall every now and then. When the galling became too annoying, I'd rub a candle on it it, and it would slick up again for a week or so.

 

[tekarra]

Several years ago I took my Post Vesalog to work and left it on my desk. A number of young engineers always came to my office during the day to ask questions or ask for assistance and would look at the slide rule not having a clue what it was. When I showed them how to use it, they were amazed.

 

[Golddollar]

In my earlier post I talked about using a scale, protractor and compass to plot legal descriptions of parcels of land by hand. I got to be friends with a lot of land surveyors and even though they pretty much were using computerized plotting programs one of them said to me, "It's good to plot a description by hand every once in awhile. It makes you think about what you're doing."