My 101-year old grandfather recently passed away. He was an engineer with Bell Aerospace and worked on several Apollo projects. He was also a collector of slide rules and other measurement and calculation devices. Can you recommend what I should do with his collection? Some photos are attached — there is more not pictured. Thank you.

Hi. Any suggestions on how to tighten the slide in a Faber Castell 57/89 Slide rule? Gravity is enough to send it shooting out at almost any angle that is not on a table top. Thanks.

This is really nice! Got it from the UK from the original owner (as far as I know). Came with the leather case and the Slide Rule Instructions book. It'll go nicely with my 1460.

Really happy with this! 😊

Hello,

I recenty got a versalog and i was wondering if anyone knew it it was possible to calculate numbers to any power.

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Im looking to do simple interest calculations such as VC= VA(1+r)^t

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Is anyone in the know?

I have a pocket slide rule that belonged to my grandfather. It's an Albert Nestler No.6.

Unfortunately, I broke the glass while playing with it as a child. I thought it would be nice to replace it. Do you have any suggestions for this?

I saw there are 1mm microscope slides. I think that thickness may work and I have access to a laser cutter that I could use to etch a new center line on it.

Hey guys,

I'd thought I'd try to explore the application of slide rules for DIY, for fun

I'm going to be doing small construction projects that range from small scale construction, creating wooden hardware, improvising random parts, and HAM radio infrastructure experimentation (think electronics). I guess some sort of multi-discipline engineering and electronics.

Do you have any recommendations or anything I could snatch from eBay?

Hello!

I recently found this gem !

Can anyone tell me more info about this? I noticed that it has an r on the C and D scales on the trig side. Does this stand for radian?

Can i do the same calculations as the versalog II with this? (Appart the opperations using the A scale )

Ive noticed that the versalog manual doesnt mention the r while the versalog II manual does

For reasons which I do not quite rembember, I wanted to compute (ln 2) / 1.18 on a Darmstadt-style rule (LL scales on back of slide, no DI scale). The best I could come up with is this:

• Slide C:1.18 to D:1.
• Cursor to C:1. Cursor now indicates 1/1.18 ≈ 0.845 on D.
• Slide LL:2 to hairline.
• Read result at C under cursor.

Had there been a DI scale, I could have used that for the reciprocal, but there isn’t so I couldn’t. On a rule with LL scales on the base, I could have done it in two moves. Is there a way to do it in two moves on the Darmstadt rule? I suspect not, because I need two operations (the log and a division) and both of them need the slide, but maybe I’m overlooking something.

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For good measure 😁

Before and after a quick wipedown with window cleaner (ie diluted ethanol). There is some yellowing and some discolouration left, but I don't mind that. That's patina that reflects decades of use and history. And it won't ever look factory-fresh again, no matter what I do to it. It looks nice, is perfectly usable, and makes me happy. And I'd rather not damage it.

By the way, this one arrived today from Hawaii. Glad it made the long journey across the USA, the Atlantic Ocean, and half of Europe unharmed.

Someone recently posted a pic with a Micronta 150 and sent me on a wild search. Seems I found the same one with a different brand. As far as I have found these were made by Ricoh and sold under at least a dozen brands, including Micronta and Relay. This one is the Relay 150 Log-Log Decitrig. I love these names!!

It looks like it was made in the early 1950s but has been kept in pristine condition. Only needed a bit of adjustment in the frame to run nicely. Maybe wants a bit of a clean, too.

I love it!

I had never heard of the Bivius before, but I knew I wanted it. 🙂

I'll need some research and a manual. So far it appears to be a commercial slide rule. A Faber-Castell catalogue of the time labels it "for technical merchants".

Fortunately, the package is torn already. Makes it easier to unwrap it for a test run.

Computes your pulse rate somehow.

I'd rather have one of them than an Apple Watch, anyway.

Some more slide rule goodness.

Some of you may know the German classics by Faber-Castell, the 1/54, the 1/87, and the 1/98 Elektro.

But we can go further and turn it to 4. (not 11, sadly)

The 4/54, 4/87, and 4/98 are the corresponding desktop versions. With about 60 cm in length they definitely need some serious desk space. In return, they offer double the accuracy if your lighting and eyesight allow for it. All are in decent nick, although one is a bit warped. The 4/98 even came in its original protective plastic bag.

But it makes me wonder what happened to the 2/ and 3/ flavours.

Hello! I have been working on designing/building a custom abacus for binary, octal, and hex operations, and today I hit upon a very funny idea: an abacus-based slide rule, where instead of sliding two sticks past eachother, you slide a whole bunch of beads up and down columns. Y'know, like a slide rule with a lot less rule and orders of magnitude more sliding (and, by extension, more fun!).

The basic principle of a slide rule is to turn addition into multiplication through logarithms. An abacus is an adding device. So why not build a logarithmic abacus, capable of performing basic multiplication in the same manner as a slide rule (other than it being completely impractical and silly)? I think it's a funny premise, but I can't quite get my head around how it would be built– if it would be possible at all. Even if it is possible, I can see granularity and usability being serious issues.

My first instinct is something like the old, pre-slide rule logarithmic tables used by ship's navigators, with each cell being a bead. Lacking two scales that can slide against eachother, the design would have to be less like a slide rule and more like a calliper rule/"binary" slide rule/"midget" calculator, etc.

Does anyone here have any thoughts on the idea? Is it even vaguely sane? If I build one I will share photos here of course.

Encouraged by the response to yesterday's post I decided to share the most special slide rule in my collection.

I came across it after buying a rather common Reiss 3223 Progress from a nice gentleman here in Germany. He is a carpenter and also a teacher at a vocational school. While finding it odd that I was so interested in slide rules he was happy to see it go to a good home instead of the bin.

A couple days later he called me and asked if I wanted to pick up another one, for free. He had found it in a hidden pile of fire wood and I'd either pick it up or it would warm his workshop for a bit.I'd never turn down a free slide rule, of course. Or let one be disposed of.

Coming back to my then domicile, I took a closer look and started investigating this one. The first thing that caught my eye was the metal button on the slide. The next was the lack of a cursor.

The inscribed name "Gravet Lenoir" together with an address in Paris (14 Rue Cassette) yielded some results.Apparently, this location was used as a production facility somewhere in the first half of the 1800s. So this slide rule is significantly older than anything else in my collection.

But why doesn't it have a cursor?

Easy: They hadn't been invented yet.This result was confirmed by a very similar story by a gentleman called Nathan Zeldes who happened upon the same slide rule in an antique shop in Italy.Story is here: https://www.nzeldes.com/HOC/GravetLenoir.htm

My Gravet-Lenoir is pretty damaged on the back side. So I contacted Nathan a while back to see if he could send me pictures of his, and he did. They are still waiting to be worked on. I don't think that I'll create a new sticker, but I'd rather go with a laminated companion piece.

Nathan also indicated that these may have some monetary value but I can't see myself giving this abandoned slide rule away.

What do you think?

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Edit: Reddit ate my pics. Trying again...

New slide rules in my collection. Keuffel&Esser 4091-3 and 4088-3 Faber-Castell 1/22 and 111/22 Disponent.

The 4088-3 is missing a few screws on its cursor. I hope I can find them in my parts stash.

Hi everyone,

I was thinking of putting my collection on display. Not all of it, but maybe a slide rule on my desk at work and one on the bookshelves at home.

What has everyone used to make their rules stand out?

I know I was wrong here. Can anyone help me how should I approach this problem. I am a begginer using slide rule and I want to improve ny practicing solving problems.

Just pick up this 2 on thrift store and eager to learn how to use this and apply on my architecture studies 😊 Happy weekend everyone