[analog31]

I have my dad's slide rule, and his HP-35. He's a retired industrial research scientist.

At my dad's workplace, every scientist had a Friden 55. The managers compared the price of the HP to the annual service contract on the Friden, and bought an HP to try out. They were going to let each scientist have it for a week, then pass it on to the next person. Instead, after just a couple weeks, the Fridens were all in the dumpster.

[exikyut]

Awesome.

It's proving a little tricky to find a picture and/or more info about the Friden 55. All I'm getting is other models. Was it mechanical?

(Hopefully some of them ended up in attics, they sound mildly interesting even if just from a historical-interest retrospective standpoint)

[analog31]

Aha, I found more hits when I entered "Friden STW." I don't know where I got the "55" from.

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

It's fully mechanical and can do addition, subtraction, multiplication, and division. I saw one of these things work, and it was quite an experience. There's a YouTube here:

https://www.youtube.com/watch?v=qKm9eM2BuM0

And a few people have published images of the service manual.

My dad said that while the Friden was accurate, it was not portable or quick, and he usually used his slide rule, notebook, and graph paper. For a chemist, slide rule accuracy was usually sufficient.

[rjsw]

I have my grandfather's pocket slide rule.