I have my father's slide rule, dating from the late 30's (K&E introduced it in 1937). He worked at the Electro Motive Company on the early diesel electric locomotives. He ended his career at Martin Marietta Aerospace, working on the Titan IIIC and Apollo programs. I entered college in 1975, and much to dad's horror I opted for an HP-25C instead of a slide rule. Oh the joy I felt when I figured out how to convert polar to rectangular on it!

In 1959, my buddy, Al, and I, went downtown, Philly, to the K+E store to get my "slip-stick", so I could be ready to start my first semester in Engr at PSU. I paid the princely sum of $22.50, no tax, for it. My wife thinks I still have it, but I can't find it. I recall that Pickett was another brand, yellow, I think, but not nearly as good as the K+E. I also recall that the first Engr class, Engr-1, was how to use the slide-rule, and featured a 10 foot model that the instructor, good 'ol Charlie Sohl, used in class. The text book was the K+E manual, with the examples given as home work and tests. Yes, I did graduate with a BS in ARoE, then went on for an MS. Retired from AREVA in 2014 after building lord knows how many nuclear plants, at the ripe old age of 73. BTW, also had a circular one, a double sized one, and a 6 inch one, just to complete the set.

I recently acquired a 4081-3, serial no 898379, with leather case, at a flea market for $2.00. I was a BEE major at San Diego State University class 1982-87. One prof required us to learn the slide rule before we could use a calculator. He had a box full of K&E 4081-3 slide rules for our use. I enjoyed it so much that I purchased one. Unfortunately, it was lost somewhere along my travels. Having fun learning again how to use this amazing piece of technology.

My father got this, Model 4081-3, in the late 40's or early 50's. Took it to college with me in 1967 and obviously was a important tool. Has another patent no., 1,930,853 and a RE 20,984 on it. There's a 116642 on the back of the slide.

I bought mine used on entering GA Tech in 1950. It has same pat. nos. as the one described above. I used it during my time at Tech from 1950 to 1959 when I graduated BEE. Had to give a little time to the USMC during that time, remember "Trumans' police action". I doubt that I could solve the simplest problem in EE on the slide rule now. I had it framed in a box frame many years ago. Still looks good.

When I enrolled in Civil Engineering at Mississippi State University in 1965, the school published, in their catalog, a requirement for all student to take a course in slide rule and recommended the K& E slide rule as fulfilling the requirement for CE-the Log Log Duplex was for other majors due to the decimal trig functions. I still have the leather case that came with mine but not the belt clip that allowed us to wear it like a sword. The slide rule marked us as the “elite” of the student body. I moved on to the HP 35 calculator within a few years.

In the academic year 1956-7 I acquired a model 4081-3 from a K&E sales rep. The serial number is 905366. Not sure if this is helpful for dating because K&E recycled their 6-digit serial numbers. The matching K&E leather carrying case is Model 4092-3S. K&E also sold leather belt clips that enabled students to wear their slide rules like swords. An annual visitor to the campus brought an engraving machine to personalize slide rules with the owners' names.. After a busy day or two, he moved on to the next college. Post was K&E's main competitor. Post slide rules had bamboo cores that provided very smooth movement, important for precise settings. Hope this is of interest.