Overview of fancier slide rules (folded scales, extended scales, LL scales)

[@normanchristopherson5434]

I was born in 1951 and learned my math on the slide rule. Of course, like everyone else we moved over to our calculators and put our rules aside. Now years later I really appreciate slide rules. Professor Herning's videos are great! Nice clear explanations and high quality video. Professor, you take me right back to slide rule class where I recall some great times learning my engineering math. Thank you professor!

[@robinj.9329]

These short, "Picket sized" rules are some of my favorites! I know Pickett is not a favorite of yours, but it was the N-600 that "Went to the Moon"! It took a bit of searching but I've finally got hold of one "NIB"! IN PERFECT CONDITION! When ever I show the "Youngsters" what we made do with; "In the Olden Days!", they are fascinated by these Kool little gems!

[@larryselvidge901]

These videos are very enjoyable! As someone that had just begun to use a slide rule when calculators came on the scene it's fun to revisit this almost-but-not quite lost skill. I now find myself carrying a slide rule in my computer bag, much to the amusement of my colleagues!

[@738polarbear]

I truly think that the Professor has done a magnificent service to maths people by making these wonderful ,informative teaching videos I have the Hemmi Post Versalog 1461 it is almost identical to the K $ E.. Hard to find now though.

[@robinj.9329]

I didn't buy my first electronic calculator till 1976! Being born just past the start of 1950, it was possible to go all through College using the slide rule for most all your engineering math. Oh yeah, those that had the bucks could get the HP 35 in '72 ? But that wasn't me.

[@MRSBRHODES1]

excellent photography, closeups and explanations. Thank you

[@jphili]

"Another day, another slide rule video. I couldn't help myself and apparently you couldn't help but watch it." jajaja 😂🤣😂🤣 absolutely hilarious

[@duncanyoung9770]

These are really well made videos. You should do another video on slide rules with Dr. White as a "guest star", maybe talk about the history of slide rules or maybe talk about some of the really advanced slide rules.

[@osvaldocristo]

Thank you! I appreciated to remember my "old days"... BTW I yet have my two European slide rules.

[@MarkKrebs]

Could you do a video for the hyperbolic trig? I've never even used that function on a calculator...

[@ProfessorHerning]

I've been thinking of doing this. Are you more interested in how to compute the hyperbolic trig functions on a rule like this, or how to do them on a rule that has specialized scales for them?

[@MarkKrebs]

I can "do the math" but I bet you've got a better technique so I'm sure I'd be interested. However I do have a couple of rules with sinh, tanh, cosh on 'em and thought I should learn also what they were used for (and if I could still use them, maybe!). I got only a canonical thermal problem reference online, and think it's unlikely that would be sufficient motivation for a whole class of really high end slide rules. There must've been some cold war, missile-man use case...?

[@738polarbear]

I don’t think that Professor Herniing could make too many of these vids,in my opinion anyway.

[@Ensign_Cthulhu]

Pi-folded versus root-ten-folded scales - 3.14... vs 3.16... Close enough for most work? The error is 0.02 or about 0.6%, and on a six-inch rule I'm not sure this is even important. Rule in question is my Ricoh No. 504 Electromecanique (sic), whose scale set is (13cm, 1mm divisions), K, DF [CF, CI, C] D, A || [T1, T2, L, S] (5 inches in 1/32) with a root-ten fold, and with trig scales decimal and keyed to C/D.

[@ProfessorHerning]

The idea behind using sqrt(10) is that it's exactly the middle of the slide rule. With this you can always set up a proportion or double operation using the folded scales without going off scale. When you fold at pi instead you don't really introduce error, but if there are no scale extensions there is a tiny range within which you will need to use an index swap to do a combined operation or proportion. I believe this is why many slide rules have tiny extensions on the folded scales -- these fix the problem you just introduced. Of course, the usual stated advantage of using pi is that you can immediately multiply or divide by pi by moving between the folded and non-folded scales.

[@ProfessorHerning]

By the way -- that's a slide rule I've never seen. Have a link to a photo somewhere?

[@ProfessorHerning]

The scale set sounds similar to the Hemmi 45K. The difference from the ubiquitous-in-US Post 1445 is that the scales are folded at sqrt(10) instead of pi. Without CIF you can't do all double multiplications without some off-scale possibilities, but you can set up any proportion that you like. If you set it on C/D but more that half the slide is "outside," then set it on CF/DF. One way or the other every target for the cursor is on scale.

[@Ensign_Cthulhu]

Unfortunately the e-bay listing I bought it through has lost its photo links and the International Slide Rule Museum doesn't seem to have a copy either. Send me your e-mail in YT personal messages and I will try to take a couple of half-decent pics and send them to you.

[@ProfessorHerning]

Perhaps I am appropriately a luddite here, but I can't figure out how to send you a PM. If you send me one, I'll send you my address.

[@riadriddick1680]

AVENDRE: J'ai 140 règles de calcul tout neuf N°57/88-Reitz-N-Etudiant & N°57/89-ETUDIANT LOG LOG.Fabrication allemagne en 1965.