⊙ AntiQuark

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Final Damn Rule

I think this will be the final virtual Pickett for the next little while. (This time I'm serious.) I've been scanning rules that are "gimmicky" or unique in some respect (mostly), and as far as I know, there are very few, if any gimmicky Picketts left. So, unless I start collecting some other brand (Ghod forbid), then there aren't any more good rules to virtualize.

This one's a neat one: Pickett N909-ES SIMPLEX TRIG RULE with METRIC CONVERSION. It comes with a set of gauge points on the slider that lets you convert between inches/cm, pounds/kg and all that. It also has a Fahrenheit/Celcius scale and a novel scale for switching from decimal hundredths to fractional 64ths.

Unfortunately, this rule wasn't intended for Canadians -- the temperature scale only goes down to -25 C.

(The layout of the scales really drives home the point that multiplication on a logarithmic scale is done by merely adding distances.)


  • At 1/17/2006 3:58 PM, Anonymous Richard Shoemaker said…

    Yeah! they are long gone.
    I still have my Picket model N 531-ES
    issued to me by CREI with thier letters on reverse side.

  • At 1/17/2006 4:52 PM, Blogger Derek said…

    It seems that Haloscan has some flaws. In particular, it wouldn't notify me when someone posted, and it also deleted old post after a while. Here, for archival purposes, are the old Haloscan comments. This thread will now be the generic comments of the virtual slide rule page.


    We have a seven foot Pickett slide rule obviously used for teaching. It is a copy of a N 1010-ES trig rule.Is there any value to a piece like this? How can it be sold? It needs to be where someone can appreciate it.
    Woody Vosler | 11.15.05 - 2:05 pm | #


    Hello Derek,

    Your virtual slide rules are simply superb. They are also very instructional. I have a Pickett N3-ESI and always wanted to try the differences on the N4 like DF/M scales and you made it possible. I also wanted to try the 525 stats slide rule for a long time.

    There are several excellent slide rule collections on the net. For example Mr. Tomozawa's collection which is beautifully scanned. See:


    The technique you are using could be applied to these collections to make them even more vivid and useful, especially to youger people who did not use a slide rule at school or work.

    Happy new year.
    Zvi | 12.30.05 - 4:44 am | #


    Hello Woody, sorry for never answering you (I think I'll do something else with this comments box so I can be alerted when someone posts something.)

    From what I've seen, the huge wooden slide rules are occasionally sold on eBay, and they go for hundreds of dollars sometimes.
    Derek | 01.17.06 - 5:44 pm | #


  • At 4/26/2006 1:37 PM, Anonymous Anonymous said…

    Thanks for going through the trouble to do this. You virtual slide rules are great.

  • At 4/26/2006 2:52 PM, Blogger Derek said…

    No problem.

  • At 12/04/2006 2:47 AM, Anonymous Anonymous said…

    Those virtual sliderules are simply Cool.

    I would like to make a Wheel ruler though - would anyone here know if THAT is possible.

    Best Regards
    Martin Vinther

    You can reach me on Mav@tele2adsl.dk

  • At 12/04/2006 10:23 AM, Blogger Derek said…

    Martin, I looked into circular rules, but it seems that JavaScript that's found in web browsers is only capable of up/down, left/right motion, but no rotation.

    To create a circular slide rule for the web, you'd have to use either "Flash" or "Java" and write an application for it.

    (I think I saw a circular SR on the internet once, but I forget where...)

  • At 6/14/2007 9:39 PM, Anonymous Anonymous said…

    Hud? I find myself using your virtual rules more often than my real one. Thank you very much! I know I owe you something!


  • At 6/14/2007 10:17 PM, Blogger Derek Ross said…

    Thanks, Mansing. Don't worry about owing anything... the simulator is on the house!

  • At 7/24/2007 4:31 PM, Anonymous Stephen F. Combs said…

    Great site! IF I hunt hard enough, I can probably find 5 of the sliderules you model! Haven't USED a sliderule in years, but I've still got (somewhere) the 6in aluminum and three different 10in ones (as well as a 20in one that I've never seen since I bought it!)

  • At 7/24/2007 6:35 PM, Blogger Derek said…

    Thanks! Using them for the novelty of it is sort of neat, but to actually use it for everyday math is a pain in the butt. I know why everyone enbraced calculators!

  • At 7/26/2007 10:44 AM, Anonymous Anonymous said…

    I just received the comments on operating the slide rule, and glanced through the first example on Simple Multiplication Rules.
    In the example regarding the square root of 4500, the last comment states "we know that "70^2 = 3600..." . This should be 4900.

  • At 8/23/2007 1:01 AM, Anonymous Mansing said…

    On downloaded version of the slide rules, Derek stated in his gallery page: "For some reason, IE gives a security warning before you can use it. . ."

    Here I found a solution: The problem is due to IE that assumes a high security level for local files. By placing a comment line like the following one on top of the html file (before the [html] tag) solved the problem,

    [!-- saved from url=(0060)http://www.antiquark.com/sliderule/sim/n3t/virtual-n3-t.html --]

    Two important notes:

    1. There is a hidden control-M (^M) at the end of the above magic line. Without that control-M, this trick won't work.

    2. change "[" and "]" to "<" and ">" in the magic line. This blog disallows html look-alike tokens.

    Mansing 2007-08-23

  • At 8/23/2007 8:28 PM, Blogger Derek said…

    Thanks for the tech support Mansing. I'll mention it in the sliderule page when I have a few extra minutes.

  • At 7/12/2008 8:52 AM, Anonymous Anonymous said…

    Your next 'virtual rule' should be an E6-B flight computer! I don't know how you'd get the center section to rotate instead of slide, but it's certainly the most widely used slide rule today.

    Also, did you know that you can use any slide rule with a CD and L scale to raise any arbitrary base to any arbitrary power?
    example: 2.72^(.69)
    Read your base from the D scale to the L scale. example, 2.72 on the D scale=4.33 on the L scale.
    multiply 4.33 and .69 using the C and D scale. a hair under 3.
    Transfer 3 on the L scale to the D scale using the cursor. 2.
    2.72^.69=2. And of course it works backwards too.

  • At 10/31/2008 12:19 AM, Anonymous Timothy Johnson said…

    Thanks!! Your virtual slide rules are great. Oh the memories. Calculators are for the weak. ha ha. I can remember taking classes on how to use them in school. Thank you for preserving these and making them useable!!

  • At 11/02/2008 7:26 AM, Anonymous John in CR said…

    I've got a pretty good idea ( I think) ;)
    You've modeled enough slide rules, but what was always the slide rule's best friend? The Addiator!
    Point #1: the addiator is just sliding cards behind a cover, which HTML can do.
    Point #2: Nobody's made one yet.

    So whaddya think?

  • At 11/02/2008 8:02 AM, Anonymous Derek said…

    Sadly, I've sort of "retired" from making slide rule simulators. You'd be amazed how long it takes. However, I'll take a look at addiators, and if I get into simulators again, I'll keep it in mind!

  • At 4/18/2009 8:06 PM, Blogger George said…


    Way to go. I think your efforts have value and are a contribution.

    Thank you for sharing you time and creativity.

    I also think that a round one would be cool.

    Have a good one (or two),

    George Ross
    Wylie, TX

  • At 4/18/2009 8:16 PM, Anonymous Derek said…

    Thanks George!

  • At 9/18/2009 11:40 AM, Anonymous Anonymous said…

    Trig scales have a problem in that cos X for smaller values (up to about 20 deg.) are difficult to set while sin and tan between 6 and about 30 deg. have relatively fine degrees of subdivision. Also, not everyone has a pythagorean scale. To this end, I worked out the trick of calculating low values of cos x as sin/tan (which on my rule, a Pickett Microline 140, move with the C scale).

    Start with C and D scales aligned. Set cursor to desired degree value on S scale. Pull slider until same degree value on T scale is under cursor. Read cos value on right-hand C index. Quick and easy.

    This may be old hat - but no manual or guide I've seen online mentions it!

  • At 9/21/2009 9:49 PM, Blogger Derek said…

    Thanks for the trig trick, I was unaware of that.

  • At 3/18/2010 5:45 PM, Anonymous Dennis Duncan said…

    Your page is a wonderful resource. Thanks for taking the time to put it together.
    I teach mathematics at university. These virtual slide rules greatly facilitate instruction on logarithyms and also educate the students on something that has been too soon forgotten. I demonstrate one on the overhead PC projection while each student works one of a hodge podge of common slide rules I've found on the cheap...classes are growing and I need more!! The virtual absence of any mention of slide rules in algebra texts is flabbergasting. Their central role in calculation lasted centuries and ended only 45 years ago. How quickly we forget.


  • At 3/18/2010 6:19 PM, Blogger Derek said…

    Thanks for the comment. I agree, they're an effective "tactile" way to explain logarithms.


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