Great video, enjoyed it very much. My Post Versalog is 60 years old and is as smooth as the day it was made. My Pickett circular rule sometimes binds up. I still remember the great slide rule wars. It was like Ford vs. Chevrolet, but with bamboo vs. aluminum!

@sliderulesurvival766

Жыл бұрын

Great point - it was like a war between Chevy and Ford! Quite frankly, I like all types of slide rules, whatever the material.

I was in the last cadre of students in my school system to be taught the slide rule and I have been a user and collector ever since (72yo). I recently met a new, younger friend who has two Phd's (not in mathematics or science who had never seen a slide rule). I gave him my Aristo BiScholar and Isaac Asimov's published book "The Slide Rule", 1965. You're never too old or young to learn the classics.

@christinemurray1444

3 ай бұрын

My husband is an engineer. He's in his mid 40s and has a collection of slide rules.

@tkarlmann

2 ай бұрын

I looked fod the book you mentioned -- they are too expensive now!

I have a Dietzgen 1734 and it is by far the best rule I've ever used. The cursor is extremely fine etched glass and is absolutely dead accurate front and back. Doing 3-place computation is a breeze on it. I never liked Picketts because they seemed to have misaligned cursors and sticky motion. The Dietzgen has plastic scales bonded to bamboo and even after 70 years it still glides like butter. The etching on the scales is sharp as a tack even under a magnifier. Just a beautiful instrument.

Nice comparison of slide rules. A few comments: AFAIK, most Pickett rules use the standard A/B and K scales and not the paired and tripled scales you have on the N4P here, so I wouldn't say that Pickett in general doesn't use the standard scales. And Pickett wasn't the only one with those paired square root scales, though they were called things like Sq (as you show on your Deci-Lon later in the video), R, or W depending on the maker. I think Pickett did do things a bit differently, as you said, but the N4 seems to be one of their most unusual rules from what I know, so it may not be the best example of a typical Pickett rule. Increased precision is one of the reasons for those paired and tripled scales on the Pickett, because they effectively lengthen the scale, making it easier to set numbers to more figures, the same way you can set something on a 12" rule more easily than a 6" rule, so there's a good justification for having them. I'm not exactly sure what you mean about instructions for using the Picketts being more complicated. Their rules are not self-documenting, no, but in general, the way you use a specific scale is the same across manufacturers. If you want to use the LL scales on a Pickett, they should work the same way on that Aristo. (Again, the N4 isn't the best example though, since its LL scales are a bit different from normal.) Learning how to use the scales is one thing, but the same scale serving the same purpose on different rules should operate the same way. Maybe Pickett manuals are harder to follow than other makers, but I wouldn't say their rules necessarily are harder to understand or use than others.

@pavelperina7629

6 ай бұрын

Thanks for the comment. I tried to find some unique slide rules and I guess Pickett N3 and N4 are the only slide rules splitting K scale into three and they are likely the most unique with the most scales (34 if I recall). Some high end Nesler Multimath and possibly other German slide rules have two R scales. Faber Castell 2/83 and 2/83N have two pairs W scales one slider vs stocks so they allow double precision multiplication, square roots and logs. 2/83 is already expensive, but 2/83N seems to be the most expensive slide rule by far. I noticed slight difference in S scale - usually it's against C, but sometimes it's combined ST+S against A. Sometimes fine division is in minutes which disqualifies it from conversion between degrees and radians. PIC and British Thornton have weird differential SD/TD/ISD/ITD scales for sin,tan,asin,atan which they consider superior, but I believe combination of S/P is more accurate. For some reason P scale seems rare on US slide rules while system Darmstadt is extremely common in Europe and P scale is on duplex slide rules as well. Also what I noticed is that cursors 4/pi are common in Europe, not so much elsewhere and once they are here, scales are often extended beyond 1 and 10 a bit so this ratio is never off-scale and also it helps when result of multiplication is close to 10 and it's not clear how to perform multiplication. I wonder if US slide rules have some tricks too. When I was trying to find unique one it's hard: Thornton AA010 (PIC221), Pickett N3 or N4. F.Castell 2/83 or 2/83N, Aristo Hyper(bo)log. Then there are some with unique materials (4 layers of brown phenolic resin impregnated textile with a paper on top, cursor from mica - i guess made by some company making rudimentary electronics during ww2 from insulation materials)

When I was a kid, just before scientific calculators became widely available, a typical problem I faced was to calculate the angle between two objects in the sky. This involved a formula like cos C = cos A cos B + sin A sin B cos (a - b) where (A,a) and (B,b) are the coordinates of the object. Doing this with tables took FOREVER. Even doing it on the slide rule was laborious, with the main error coming from the addition. If you didn't want to resort to pen and paper, you needed a way to add/subtract 2 numbers - so you convert an addition problem to one of division by writing x + y = (x/y + 1) y and add 1 in your head! Even the most primitive scientific calculator was an enormous time saver. But it is satisfying to know that with my slide rule and my Abramowitz & Stegun I can build a Saturn V if someone really wants one after the apocalypse.

@sliderulesurvival766

2 жыл бұрын

It's great you think that way. In my opinion, we should go back to teaching math using slide rules and multiplication tables.

@mgmartin51

Жыл бұрын

I just saw another video referring to the NASA engineers adding numbers with their slide rules, and I smugly thought “Oh, she meant multiplying “ and here you taught me how to add using my slide rule! Cheers!

Thank you for your video. Regarding 15:49, an alternate method for finding the square root of a number is to use the Log Log scales, because raising the power of a number to its 0.5th power is equivalent to its square root.

Cool video. Thanks for sharing!

@sliderulesurvival766

4 жыл бұрын

Thank you for your kind remarks.

I've used a Post Versalog for MANY years, until I drained my meager bank account to, and drove to Chicago, with my $400, to actually get the HP-45 Calculator. Before then, I was so good with my Slide Rule, that I was able to outperform a group of younger College students with my slide rule doing data reduction, and they with their TI Calculators! I must also say, that in the years I used my Post Versalog, I NEVER had any issues with wood warping, etc. That Versalog always operated smoothly. I did notice, however, that the longer Rule you Showed near the beginning of this video was improperly aligned -- with a noticeably wider gap at one end. Terrible disrespect for an instrument!

Pickett didn't marked those scales "AB" and "K" just to be different but because those scales do NOT represent squares (x^2) and cubes (x^3) but the inverse functions, square roots (x^1/2) and cube roots (x^1/3). You are totally missing the point. It's not some kind of eccentricity. The traditional AB scale is two decades long, while the two new Sq1, Sq2 scales are half decades long making them 4 times more precise than a single AB scale. It was a major improvement introduced at the end of the slide rule era. If it wasn't for the pocket calculator, the AB would have gone extinct. All majors slide rule makers were replacing double decades scales with multiple half decades scales. It's not a "Pickett" thing. Sun Hemmi, with the Versalog and Versalog II, K&E. with the Deci-Lon, etc. were all doing the same. Versalog isn't a manufacturer. It's the name of the 1460 model made by Sun Hemmi and sold in USA by The Frederick Post Co. Your Dietzgen slide is severely misaligned or warped. You can adjust the space for the slide with the screws on the body. See the instructional manual.

@billl605

2 жыл бұрын

I saw that gap close when he picked it up, its probably just a loose screw.

@pavelperina7629

8 ай бұрын

Interesting info. It's also interesting that American rules are different than European (Czech and German) ones. It seems they usually lack pythagorean scale, sometimes they have two tan scales (i think it's not necessary due to CI, have to try) and sometimes they even have hyperbolic trig. scales which are functions I never used in my life (maybe they are used in construction or mechanical design). Also I think that every Czech slide rule has cursors for fast HPkW conversion and fast conversion between diameter and area of circle (2 on CD scales matches PI on AB scale) so it's possible to get volume of cylinder by one move of slider. But maybe american rules have other tricks. Have square roots for 1-10 and 10-100 is certainly nice. But once when I wanted to get square root of 62 or something, I found out that most accurate way is 0.64^1/2=0.8 on LL0 and not using AB vs CD (it was not that obvious case, something like sqrt(7.8^2). But it needs to have duplex rule and some creativity.

@thorhilda

8 ай бұрын

​@@pavelperina7629 Some continental differences can be explained by differences in school curricula, and others by the predominant industries in each region. ______________ Hyperbolic trigonometry has many applications in various fields, such as engineering, physics, biology, and astronomy. The classic example of the use of hyperbolic trigonometry is that of suspended cables, which form a catenary curve. This is relevant for mechanical and architectural designs, such as bridges, power lines, and arches. And, it is easy to visualize by college students. That's why it's often cited. However, hyperbolic functions also appear in other contexts, such as: Cartography: The Mercator projection, which maps the surface of the earth onto a cylinder, uses the inverse hyperbolic tangent function to relate the latitude of a point to its y-coordinate on the map. Navigation: The hyperbolic cosine function can be used to calculate the distance between two points on a sphere, such as the earth, given their latitudes and longitudes. Towed objects: The relative motion of a towed object, such as a glider or a buoy, behind a moving vessel can be modeled by a system of hyperbolic equations. Missile guidance: The optimal trajectory of a missile in the atmosphere, taking into account the effects of gravity and drag, can be expressed in terms of hyperbolic functions. Radio propagation: The shape of the radio waves emitted by a dipole antenna can be described by a hyperbolic function. Biology: The logistic function, which models the growth of a population or a cell culture, is related to the hyperbolic tangent function. Astronomy: The orbits of some comets and other celestial bodies around the sun are hyperbolic, meaning that they do not return to their original position. _______________ Using my Versalog, I can estimate the square root of 62 on the R2 scale as a value between 7.87 and 7.88. That’s pretty accurate for a slide rule.

The one on my hp15c

I guess “That factor of safety “ is why most things built in the past ie., the 30’s,40’s and, 50’s were over built due to the inaccuracies of the slide rule.

@sliderulesurvival766

4 жыл бұрын

I partially concur with what you say. Factors of safety are always applied because we cannot know all conditions of service and various conditions interact. When you consider the multiple dependencies in engineering problems, the engineers of previous times probably applied more factors of safety than is done today because we have different computational tools and more computing power at our disposal than say the engineers who helped put Apollo 11 on the lunar surface. The slide rule could provide say 3 digits on it and therefore there were limits to its computing capabilities. Having said that, many things in large civil works like a dam or a power plant don’t need lots of digits in an answer. The slide rule, when applied properly, gives us a unique insight as to the dependencies between variables once you master it. BEGIN OLD MAN RANT IMO, the slide rule’s true value is that an engineer or scientist could not go to a box (the electronic calculator, spreadsheet, etc.), plug in some numbers, and get an answer without exerting some thought. I find that the simple act of writing things down compels me to organize what I want to find, what information I have, and then work into the answer. (I note that I carry 2 slide rules every day and try to practice with them). IMO, it is far more important to manipulate the concept in your mind and then do the computation at the end than to plug numbers into a box hoping that you’re going in the right direction. By definition, you have to understand what I will refer to as “Pre-Calculus Math Facts” for you to make intelligent use of a rule with exponential or trigonometric functions. A calculator (and math textbook’s use of electronic calculators since the mid-1980’s) allows the user to become more of an operator than a thinker because it is easy to punch in numbers and produce an answer. A slide rule requires more thought to use. The first chapter of many manufacturer’s slide rule booklets plus the numerous books published from the early 1900’s up into the early 1970’s would then focus on the MAGNITUDE of the answer. The act of simplifying the answer using “easy numbers” and learning how to think in scientific notation helps immensely when performing back of the envelope calculations. How many texts on elementary scientific computations written today have this basic information on learning how to estimate included in their introductory material? I’d guess very few. I once had an older electrical engineer pull out his Post pocket slide rule and perform basic mental calculations associated with figuring out apparent power given some basic information. When we checked his answer with a hand calculator, we found he was off by say 1 or 2 digits in the 3rd place of his answer. Not too shabby for a mass manufactured piece of plastic given that I punched in the same set of numbers in my $120 (1985 cost) HP-11C with little understanding of what he did (I was a college engineering student at the time). I cannot resist my favorite example. If you want to perform elementary vector calculations with an electronic calculator, you need to understand the keystrokes sequences in the given device (one electronic platform being entirely different from another). If you get a keystroke sequence incorrect, you will get an error because of you have input numbers in a format that your device does not “like”. Even assuming you make it past the input hurdle, the modern electronic calculator most engineering or science students would buy has a user interface that is difficult to use for vector manipulation. The slide rule, by contrast, easily converts between polar to rectangular forms (again with a little practice and a firm grasp of trigonometry) common in vector operations. The slide rule does this without the need for batteries, the need for constant firmware upgrades, risk of malware, hacking, or a user’s manual beyond what you get from the slide rule vendor. In days past, a well laid out slide rule (with an informed user) saved many an engineer or scientist from carrying around handbooks filled with arcane pieces of information since all the common data could be placed on a slide rule scale. I’d ask you to consider the fact that the Hoover Dam, the Empire State Building, and the SR-71 spy plane were all built with only paper, pencil, and a slide rule. Granted, we had teams of people possibly working on the same portions of a problem and no doubt it may have taken longer to do these tasks. Even so, the fact that this humble tool did so much to build our modern world is simply astounding to me! END OLD MAN RANT

@TheRockMorton

3 жыл бұрын

@@sliderulesurvival766 Most excellent discussion! Many thanks. In 1974 our college chemistry professor only allowed a slide rule for classroom calculations. Learning scale relationships and keeping the mind focused on each calculation step of a problem was the goal, which is mostly lost in the use of digital calculators. The slide rule is an amazing tool.

@GoSlash27

3 жыл бұрын

There's a big difference between precision and accuracy that people don't grasp until they play with slide rules. A slide rule will give you a 100% accurate answer if used properly, but only to 3 or 4 decimal places. A calculator will give you a highly precise but inaccurate answer to 10+ decimal places if you didn't enter your numbers to the same precision, because no answer can ever be more precise than the question asked. The real reason things were overbuilt in the past is because they were built to last instead of being disposable.

@BrianTRice77

7 ай бұрын

First, overbuilding wasn't predominant in the past - it's predominant in what survived from the past! Anything not overbuilt tended to fail because no one knew or could design for all the factors that would fatigue and lead to failure of structures or engines. Overbuilding in civil and other engineering products of the past compensated for the inability to fully know and simulate the environment and loads encountered. No team of slide rule users is going to perform FEA or CFD. Computers do that by manipulating whole arrays of numbers in ways that a room full of engineers could not do repeatedly at scale. Now, I want to see if there's a way to perform FEA using analog devices, even if it has to be done in a computer simulation just to save time and avoid hoarding identical slide rule models...

@charlesward8196

3 ай бұрын

⁠@@BrianTRice77Trying to broaden my knowledge here, even at age 70+; what do the acronyms FEA a CFD stand for, and what are the operations used to find? I am obviously not going to perform the calculations, but I just learned about the “geometric mean” today, so for some of us, learning never ends. Thanks!