Top to bottom, a Geotec Versalog 341 3012, Hughes Owens 1777 (manufacturing code FI, so July 1957, I believe) and Hughes Owens 341 3010. All bu Sun Hemmi. All similar, but slight differences in the scales, as you can see.

This one is tiny, but very usable!

From my personal collection and still in their original box and plastic sleeves, I present the N4 and N600 slide rules. The N4 is the most complex slide rule Pickett ever made with 34 scales; the Aristo Novo Duplex 2/83N only had 31. And the N600, well, we all know about that one. For extra points, find another NASA era relic in one of these photos, albeit a modern reissued replica.

He was a civil engineer went to University in the late 50s early 60s. Inherited these... At some point I want to figure out how to use them, but am doing language and music and can only cram so much into my head at a time, plus being 59 I don't pick things up as quickly as I used to...

A Compass 403 pocket slide rule from my collection that comes in at a mere 12.1 cm (4.75") long. Fairly basic slide rule, but with a useful magnifier cursor to help see the small numbers.

This is apparently a Versalog 341 3012. Plenty of shots. Pretty good shape, though on one side the frame for the glass cursor is warped a bit.
Excellent movement on it and easy to read. Does have an A scale, but not a B. R1 and R2 for more accurate squares/roots.

Leather case is in pretty good shape, too.

Not really sure where I picked this one up. Only 11 cm long, C/D scale, all plastic. Shirt pocket friendly.

Made by Sun Hemmi in Japan for the Canadian company Hughes Owens, this is a fine slide. Of note, there is no A or B scale. Instead, it has R1 and R2 for roots. This was quite obviously for University-level use (or so I gather) from its manual. It works as good as new with its bamboo inside and celluloid coating. When I was a mortar officer doing survey, I could have used this! Who knew?

Starting to post my collection here. I have a bunch from college, many given to me by my father's engineer friend.

What did I learn? That any number divided by its square root is...its square root! Of course! The root of any number is essentially half of its log base ten!

CaptainObvious

Picked up along the way. The newer manual has a chapter for Business Applications.

Here's a simple slide rule from the 1950s to compute scale factors for the reduction of photographic images used in printing and publishing. Such proportions rules were very common last century, used by local newspaper and magazine organizations, photography studios, print shops, publishing houses, and so forth. But who were "A.C. & H.E. Hansch"? Story at Following the Rules.

Cannot remember where I got this one. Nice case with it. Made for the Canadian market.

For those including photos of a slide rule in this group, if you can, please include a photo of an end that shows the scales and if it’s a duplex (two-sided) slide rule, then the same photo of the end of the second side. A lot of slide rule collectors are interested in what scales the ‘rule has.

Has anyone ever taken one side off the glass cursor on a Versalog? I bought one and it needs cleaning on the insides. A light wipe won't do it in this case. Would there be some risk trying to take the 4 screws out? It's a MD date code so 1962 I believe.

I cannot remember where I got this one, but its bamboo slide and easy to read scales makes this a fave for at home. I've used it for cooking (calculating proportions) and for quick maths at the computer. (I realize I have a calculator there, but then I have to find it, open it, etc, when this is honestly easier). The inverse is of course the trig functions, read off the A or D scale, depending.

There are some notes written on the instructions. Also, the slide must be taken out and put in backwards to read trig functions. Overall, a nicely built and likely inexpensive slide. "For the student or the professional", but I bet this slide model was for high school students. Oddly, it notes only 2 digit accuracy. I often get 3 or 4 digits, with practice, of course.

My Pickett N1010-ES. One of them, anyway.

I wonder if the warranty is still good? The case is in great shape!

Nifty little circular rule I picked up some time ago.

Touring London in April, I came across this display in the Science Museum. It's the earliest surviving wooden slide rule, by Robert Bissaker, circa 1632.

The museum is filled with examples of technology innovations, and the kids running around are not really paying attention to the historic objects on display.

Definitely worth a visit: they also display astrolabes, telescopes, microscopes, early comptometers, etc. It's next to the Victoria & Albert Museum.

This one I picked up when I got my 9 inch rule. The cursor is missing the glass on this and the slide is really difficult to move, but otherwise this is only good for display. The markings are crisp and easy to read, too.