The case of the slippery stick

KC Boxbottom

September 22, 2015

My granddaughter, Aly G, was helping me organize my office. "This could be a lifetime career if you want it," I kidded her.

"That's OK, Grandpa," she replied as she held up a black leather case she had unearthed.

"What's this?"

"Wow!" I told her. "I've not seen that in dog's years. That is a slipstick. A Pickett N3-T Power Log Exponential slipstick, to be precise.”

"A slipstick?" I could tell by her look that she thought I was pulling her leg. Again.

"That's what us kool kidz called it back in the day. Properly speaking, it’s a linear slide rule. This was the way to calculate numbers before electronic calculators.”

She was looking more and more puzzled, so I figured I'd better show her how it worked. Amazingly, as I started handling it, I remembered how.

"Looks complicated," she told me.

"Well, it is more complicated than a calculator and nowhere near as precise. But it still has one big advantage over calculators: The slide rule forces you think about and understand the math and what you are doing in a way that no computer or calculator ever will. When you know how to use a slide rule, you really know how to do math.”

"In my troubleshooting workshops, I teach how important it is to understand a packaging machine before you can work on it. This is much the same thing.

"Would you like to have it?" I offered to my granddaughter. “I can teach you how to use it and you can impress your teachers.”

"Fiddlesticks on slipsticks!" she exclaimed. "Can I have this pocket calculator I found instead?"

Known as the Changeover Wizard, John R. Henry is the owner of, a consulting firm that helps companies find and fix the causes of inefficiencies in their packaging operations. He has written the book, literally, on packaging machinery ( and is the face and personality behind packaging detective KC Boxbottom, the main character in Adventures in Packaging, a popular blog on

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