Slide rule
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I have about 20 slide rules. Been collecting them since High School.
Which one do you have? Let me know what the scale names are (letters on the left) and I'll see if I have a manual for it (or something similar). I happen to collect the manuals too!
Which one do you have? Let me know what the scale names are (letters on the left) and I'll see if I have a manual for it (or something similar). I happen to collect the manuals too!
It is a Pickett Microline 120. I don't collect them, I would like to know how to use it so I'll have an upper hand when the power fails and society collapses, or something like that. I just would like to be able to have that knowledge.
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Here's a place to get started: https://sliderulemuseum.com/SR_Course.htm
goldlizard
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Quick notes:
C & D are used to multiply & divide.
K for doing cubes and cube roots
A & B for doing squares and square roots
S for sin & asin
T for tan & atan
L for log (base 10)
C1 is the C scale backwards. Usually for reciprocals.
You need to be able to track the power of 10 and add on your own.
My favorite slide rule I have is a Sun Hemi 257 designed for Chemical engineering. It has molecular weights marked on it!
C & D are used to multiply & divide.
K for doing cubes and cube roots
A & B for doing squares and square roots
S for sin & asin
T for tan & atan
L for log (base 10)
C1 is the C scale backwards. Usually for reciprocals.
You need to be able to track the power of 10 and add on your own.
My favorite slide rule I have is a Sun Hemi 257 designed for Chemical engineering. It has molecular weights marked on it!
Cool. I know some of the functions, just never did it analog style. I like the idea that one can describe a nose cone and a flight path through the solar system with the same little plastic tool.
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gpoehlein
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If you can find a used copy anywhere, Isaac Asimov wrote an excellent book on using the slide rule. I don't remember the title right now (I'm at work and they've locked out all shopping sites including Amazon), but I learned a lot from reading that book. Unfortunately, I haven't used one since the seventies, and I've pretty much forgotten most of the technique.
Oh, and no photo of it, but I have a slide rule tie tack - it actually works too (although, as you can imagine, the resolution sucks since it is only about an inch and a half long!
).
Oh, and no photo of it, but I have a slide rule tie tack - it actually works too (although, as you can imagine, the resolution sucks since it is only about an inch and a half long!
).
JAL3
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I used to carry an old slide rule around in my brief case but never really used it. Then during a geotech final, my HP calculator died and I finished the exam with the slide rule. The prof, a young guy with a fresh PhD wanted me to show him how to use it. He said he had never seen a real one before.
When in private practice as an engineer, I kept mine in a glass case on the wall with a sign: "in case of emergency, break glass".
When in private practice as an engineer, I kept mine in a glass case on the wall with a sign: "in case of emergency, break glass".
My stepfather was an electrical engineer for the DOE in the 70's, he had a couple of slide rules and a nice drafting set. I used the drafting set sometimes but just never played with the slide rule, I only used an architects ruler for measuring.
stickershock23
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I have a couple. Pretty rusty at using them. my some came in a grabbed one.. starting walking out of the shop... looked back at me and said "where the Inches marks??" LOL
I told him "its a calculator it doesnt use inches as a standard" he gave me the oddest look.
I told him "its a calculator it doesnt use inches as a standard" he gave me the oddest look.
I'm a "young guy." Scientific calculators were invented by the time I started learning math. I bought a TI-35 in the 5th or 6th grade with my paper route money! By the time high school came around, I found I needed a little more challenge, so I brought a slide rule to classes and used it instead of those fancy calculators. I recall my Chemistry teacher, a great guy, standing near me during an exam watching me work the problems with the rule. After the exam, he asked me why. I just shrugged and said class was to easy otherwise. He chuckled, shook his head, then tutored me a bit in using some of the more complex scales.
At the end of the year, he gave me the Sun Hemi 257.
At the end of the year, he gave me the Sun Hemi 257.
sandman
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Back in the 60's when I was an engineering student at Michigan State all of the engineering students, me included, had a slide rule in a leather belt sheath.
We were cool!
Oh, yea...and a pocket protector.:wink:
The ladies didn't stand a chance.
We were cool!
Oh, yea...and a pocket protector.:wink:
The ladies didn't stand a chance.
aditat2
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I still have my old slide-rule around here somewhere. Has been with me for over 50 years. Used it all through school. Don't remember how to use it any more since the advent of the calculator, but maybe I should break it out and get acquainted with it again. It is a cool tool.
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https://www.sphere.bc.ca/test/sruniverse.html is another good resource.
I've ordered new circular slide rules directly from https://www.concise.co.jp/en/products/list.php?category_id=30
I've ordered new circular slide rules directly from https://www.concise.co.jp/en/products/list.php?category_id=30
Sooner Boomer
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I learned how to use slide rules in several classes in high school. In college, you could always tell the engineering students by the "holsters" on their hips (the bigger, the better the grades...). I used to have a K&E 10" bamboo laminated, and an HP (12"). Wonder where they got off to?
I remember reading Heinlein's "Rolling Stones" a few years ago. Papa Stone calculated the trajectory from the moon to Jupiter using a (circular?) slide rule. I broke out into a laugh, startling the cat. It's (about) 450 MILLION miles to "Big J". The MOST a slide rule, even a good one, is 4 digits (and you're guessing at the last one). That's one in a thousand. Of course when Heinlein wrote the story there weren't computers*, certainly not like there are now.
*"Computers" were originally people who sat around all day calculating (computing) things like logarithms, square/cube roots, and trig functions and writing them down in a book. How many of you know how to do complex calculations using logarithms and a look-up table? Heck, how many of you even *have* such tables. Well, you're not really prepared for the end of civilization (or living off the grid), are you?
I remember reading Heinlein's "Rolling Stones" a few years ago. Papa Stone calculated the trajectory from the moon to Jupiter using a (circular?) slide rule. I broke out into a laugh, startling the cat. It's (about) 450 MILLION miles to "Big J". The MOST a slide rule, even a good one, is 4 digits (and you're guessing at the last one). That's one in a thousand. Of course when Heinlein wrote the story there weren't computers*, certainly not like there are now.
*"Computers" were originally people who sat around all day calculating (computing) things like logarithms, square/cube roots, and trig functions and writing them down in a book. How many of you know how to do complex calculations using logarithms and a look-up table? Heck, how many of you even *have* such tables. Well, you're not really prepared for the end of civilization (or living off the grid), are you?
powderburner
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(Yes, I am talking about slide rules.)
Since the accuracy of your calculations depends on reading all those little vernier hashmarks, a larger slide rule (well-made) is easier to read and use. Those little 6-inch things are pretty much just toys when it comes to doing serious calcs. Find a 24-inch slide rule if you are going to get serious.
The markings are all based on logarithm math. That stuff is interesting in itself, but you will start showing yourself to be a super-nerd if you start asking your friends questions about logs.
In high school, we pretty much all started using hand calculators. I remember the first TIs costing like $500 for a pretty big box that could only add, subtract, multiply, and divide. I still shake my head now, anytime I cruise the store shelves and see modern hand-helds that have a buzillion functions (and graphing) for like $10.
When I started college we all used calculators, but us engineers were also still required to take two labs to learn slide rule operations. Many many hours spent in the old Quonset huts (not airconditioned, either) slipping those sticks. If I had a nickel for every......
Since the accuracy of your calculations depends on reading all those little vernier hashmarks, a larger slide rule (well-made) is easier to read and use. Those little 6-inch things are pretty much just toys when it comes to doing serious calcs. Find a 24-inch slide rule if you are going to get serious.
The markings are all based on logarithm math. That stuff is interesting in itself, but you will start showing yourself to be a super-nerd if you start asking your friends questions about logs.
In high school, we pretty much all started using hand calculators. I remember the first TIs costing like $500 for a pretty big box that could only add, subtract, multiply, and divide. I still shake my head now, anytime I cruise the store shelves and see modern hand-helds that have a buzillion functions (and graphing) for like $10.
When I started college we all used calculators, but us engineers were also still required to take two labs to learn slide rule operations. Many many hours spent in the old Quonset huts (not airconditioned, either) slipping those sticks. If I had a nickel for every......
Old Nerds, please don't take offense at this, but I would love to give your old 'rules the home they deserve. Please drop me a PM.
Back to my story. Logs.. Yes logs. Well, I was trained to be a nerd. I ran out of math in HS so I took classes at the Community College during my Soph, Jr, and Sr. years. I recall being completely confounded about why the log function existed. Yes, I understood it was the inverse exponential, but why were we spending so much time on it? Then it dawned on my while riding my bike to the CC for class (no I couldn't drive!), it was the basis of the slide rule! A revolution in computation.
Back to my story. Logs.. Yes logs. Well, I was trained to be a nerd. I ran out of math in HS so I took classes at the Community College during my Soph, Jr, and Sr. years. I recall being completely confounded about why the log function existed. Yes, I understood it was the inverse exponential, but why were we spending so much time on it? Then it dawned on my while riding my bike to the CC for class (no I couldn't drive!), it was the basis of the slide rule! A revolution in computation.
The wooden ones are.
powderburner
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Harumph!!
gpoehlein
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I was in high school right at the cusp of the electronic calculator (graduated in '74). We had to use slide rules in chemistry because calculators weren't out yet. I had a really cool circular slide rule that had a rectangular base with a card that slid out from inside - the card had the periodic table on one side and useful formula and information on the other and on the back of the slide rule. The plastic case even read something like "Physics is Phun!" Sadly, I left it on the dash of my car at college and it warped in the heat, making it totally unusable.
During my senior year of high school, those of us in the honors chemistry class were offer the oportunity to buy a brand new electronic calculator that not only did the four functions, but had three buttons on the top that did squares, reciprocals and square roots. That baby set me back $130. A year later, when starting college, I got my first TI that had scientific functions (which was one reason the circular slide rule was left on the car dash). If was truly amazing in the mid seventies to watch how fast calculators came down in price while that "magic price point" of $129 gave us the newest, hottest and extra features. Anyone remember the old HP calculators with reverse Polish notation? (I'm not making that up and it ISN'T an ethnic joke!)
During my senior year of high school, those of us in the honors chemistry class were offer the oportunity to buy a brand new electronic calculator that not only did the four functions, but had three buttons on the top that did squares, reciprocals and square roots. That baby set me back $130. A year later, when starting college, I got my first TI that had scientific functions (which was one reason the circular slide rule was left on the car dash). If was truly amazing in the mid seventies to watch how fast calculators came down in price while that "magic price point" of $129 gave us the newest, hottest and extra features. Anyone remember the old HP calculators with reverse Polish notation? (I'm not making that up and it ISN'T an ethnic joke!)
Just because this is a hobby site and we like to build things..
https://www.instructables.com/id/Making-Your-Own-Slide-Rule/
https://www.instructables.com/id/Making-Your-Own-Slide-Rule/
I think I went through 5 HP calcs - 11c, 15c, 28s, 48sx, 48gx. I still have the gx stashed away. I was really big into assembly programming on that thing - it had a very active hacker community. I was very disappointed when HP left the handheld calc business.
The good thing is, there is a very nice HP48 emulator out for android. I pretty much use that all the time, but it doesn't have that satisfying click feel to the buttons
The good thing is, there is a very nice HP48 emulator out for android. I pretty much use that all the time, but it doesn't have that satisfying click feel to the buttons
gpoehlein
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It's just amazing to me how the technology (computers & electronics) have changed in the last four decades. I worked for Radio Shack for a year back around 1980, and we had a collection on RS catalogs (remember when they used to mail those out?) going back to around 1970 - the 1974 catalog has the first electronic pocket calculator listed for $129. And that model was just four function - no memory or anything. And, going through the catalogs, you could see the price drop by half each year. Now, they practically give simple calculators away as the prize in cereal boxes.
And my first digital watch (mid 70s) had red LEDs for the digits - you couldn't read it in bright light! Then a couple years later, the first LCD watches came out and I had to have one. I quickly noticed that if I drove with my left arm hanging out the driver side window in the summer heat, the LCD display turned completely black until it cooled back down. Never seemed to hurt it, but it unnerved me the first time it happened.
And computers? My first home computer was a TRS-80 purchased in 1978 - it was a Model I, Level I unit with 4K (that's K, guys, not Meg or Gig) of RAM and a portable cassette recorder for storing programs and data. Not too long ago, I bought a Raspberry Pi that, while small and primitive by PC or Mac standards, is still light years beyond that old TRS-80. And that was just 35 years ago! Like I said - truly amazing!
And my first digital watch (mid 70s) had red LEDs for the digits - you couldn't read it in bright light! Then a couple years later, the first LCD watches came out and I had to have one. I quickly noticed that if I drove with my left arm hanging out the driver side window in the summer heat, the LCD display turned completely black until it cooled back down. Never seemed to hurt it, but it unnerved me the first time it happened.
And computers? My first home computer was a TRS-80 purchased in 1978 - it was a Model I, Level I unit with 4K (that's K, guys, not Meg or Gig) of RAM and a portable cassette recorder for storing programs and data. Not too long ago, I bought a Raspberry Pi that, while small and primitive by PC or Mac standards, is still light years beyond that old TRS-80. And that was just 35 years ago! Like I said - truly amazing!
