I made me a slide rule

pilote said:
...good God man, why?...the invention of the transistor and ic chips put that infernal device out of business...yeah i remember how to use one, but i don't want to use an abacus either

hp 12c forever...
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spoken like a business major.

Engineers had HP 41's or HP 15c's.

I had an HP 41 with a Quad memory pac, the math pac and the stat pac. Also had the card reader. Still do out in the garage.
 
Don Luis said:
He he, I have these things too, I guess I'm just a geek...

Luis


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My mother used an abacus. Before the days of portable calculators she would do book keeping for small businesses. She carried the abacus with her to use as an adding machine. I still have it. Somewhere.
 
hp 12c forever...
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Engineers had HP 41's or HP 15c's.
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Interesting. I was a math major, not much to do with business or engineering, I worked as a statistician for a while, I admit to have forgotten most of what I learned in college.

I often have this one in my shirt pocket, bought it cheap at a local street market.

Luis


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Edited:

Found some info on the HP 97, which is what we had in the office when I worked as a statistician for the Mexican government (1978-1980), here's a pic.
 
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smegs, thanks, I had seen the sites in the first and second links you posted, but not the third one, it's cool.

Luis
 
it comes w/ a pocket protector.
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Yes, something like this.

Luis

Edited: I couldn't resist taking a picture of the small pencil in the pocket protector, it's been around unused for years.


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It's been a number of years since I used a pocket protector.

For a hoot, try reading this 1940 pamphlet from K&E on how to choose a slide rule.
(the pages are at the bottom of the web page.)
http://www.sphere.bc.ca/test/ketour.html
 
knarfeng said:
spoken like a business major.

Engineers had HP 41's or HP 15c's.

I had an HP 41 with a Quad memory pac, the math pac and the stat pac. Also had the card reader. Still do out in the garage.
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So did biologists, and I still have them.

I still have slide rules as well.

My watch actually has a slide rule on it, and yes, I do use it.

The students love to see me do it, and for some reason, nobody laughs.
 
One of the older engineers at work was reminding me about how when calculators came out the guys would check with a slide rule to make sure the durn thing was right. IIRC some of the early calculators had bugs in the algorithms and would occasionally give a wrong answer.
 
A friend of mine always used to add figures manually, and when his customers checked the number with their pocket calculators, they would get different answers. Careful recalculating would always support his original answer.

It's not easy pushing buttons down a long list and not hit a wrong key now and again. That's why I liked the calculators with the "paperless tape" so you could match your entries to the original column of figures.
 
The HP15C is one of the most perfect products ever made. I have an iPhone Ap that emulates the HP15C too and I love it. I don't carry my 15C anymore because it's precious. I also have 15C emulators on all of my PCs.
 
Gollnick said:
I actually have a sliderule ap on my iPhone. The young bucks think its funny until they see show fast I can get darn close to the answer... close enough for most practical purposes.

The art of estimating and the concept of "close enough" is something which is being lost. I'm aways amazed to ask some young engineer, "What shall we tell the manufacturing test folks that the voltage at this node should be?" And the young kid gets out his laptop and fires up pSpice and five minutes later announces, "3.312548 Volts, Sir."
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That is something that has always annoyed me about habitual calculator users; where does the number come from and what does it mean? After so many digits you lose the precision and accuracy you thought you had. You're simply attaching extra digits to the answer. Students always begrudge the fact that I stress significant figures but there is a place and purpose for such rules.

Gollnick said:
Now, if you really want to get to know the sliderule, forget scanning the scales. Do a little research and find out what the math behind the scales is. Then, have Excel make up each scale in tabular format and then graph it for you. Use that graph to mark your scales.
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It's not complicated at all to make a rule, but I have been having some difficulty in getting the measurements right for a circular slide rule. I am going to check out the other sites listed here.
 
Gollnick said:
The HP15C is one of the most perfect products ever made. I have an iPhone Ap that emulates the HP15C too and I love it. I don't carry my 15C anymore because it's precious. I also have 15C emulators on all of my PCs.
Click to expand...


A friend of mine used to collect old HP calculators. Must ask him if he has one of those.

What's the 15C emulator app for the iPhone called? Probably something complicated like "HP 15C Emulator". I'll have a look for it.
 
gajinoz said:
What's the 15C emulator app for the iPhone called? Probably something complicated like "HP 15C Emulator". I'll have a look for it.
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There are actually several now. I have the actual HP one (yes, HP still sells the HP15C, it's just that it's now an iPhone Ap). It's expensive as iPhone Aps go. And it makes this annoying key click which I have simply had to accept. I'm told that they made the ap by first writting an iPhone program that emulates the "processor" on the HP15C. They worked on that until it passed the orignal manufacturing test vectors for the HP15C. And then putting the actual, orignal HP15C microcode into it. So, it is an exact emulation of the 15C. The only enhancement is that if you press on the HP15C badge, it "flips" over so that you can see the reference stuff that's printed on the bottom of a real 15C.
 
I really like HP calculators, especially the ones with RPN logic. I actually have a hard time using the algebraic calculators.

My oldest daughter always had a different thought process when working math and physics problems in school. So one day I showed her my HP 15C and showed her how the RPN worked. She really liked it. My wife and I got her an HP33S (I think that's the one, scientific with RPN) for her birthday. In college she needed a graphing calc for a math class. She asked her professor if a certain model HP calculator was adequate for the class. He was surprised that someone liked and used HP RPN logic calculators.

I also made her a paring knife. I set ss pins in the handle with logrithmic spacing (used my plastic yellow Pickett slide rule). She loves it. The log spacing looks really good on the knife.

Ric
 
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