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    Re: recommendation for slide rule ?
    From: Paul Hirose
    Date: 2009 May 21, 16:00 -0700

    Greg Rudzinski wrote:
    > Gary,
    > 
    >      It does appear as you have illustrated that the K&E 4080 has
    > multiple advantages over the Pickett.
    
    The K+E 4080 family has the disadvantage that its rear (trig) side lacks
    a C scale. While you can easily do 2 * sin 20°, or 2 / sin 20°,
    something like 2 * 3 or 2 / 3 requires flopping the rule to the other
    side. Also, if you simply want to read the value of sin 20°, you must
    first align the S and D indices.
    
    Like most high-end rules, the Pickett N3 you mentioned has scales C and
    D on both sides of the rule, eliminating the above annoyances. Scale S
    is not adjacent to D as on the 4080 family, but this is a matter of
    taste rather than computational power.
    
    The Pickett N3 is one of the few rules with a double tangent scale.
    This doesn't give the rule any greater accuracy or range, but sure makes
    life easier when dealing with tangents and arc tangents.
    
    Lest anyone think I'm a Pickett shill, let me say the only slide rule 
    I've ever liked enough to buy two identical ones is the 10 inch K+E 
    4181! It's a nice competent workhorse with everything I need but no 
    frills. The shortcomings I pointed out above are charming blemishes. 
    Part of the fun is working around them. However, if using a slide rule 
    were just a job, I'd rather have an N3.
    
    I believe the Pickett "Eye-Saver" yellow was just a marketing gimmick.
    It's not any easier to read, and I find a white rule more attractive. As
    far as I can tell, readability is a tie.
    
    Note the Pickett doesn't necessarily mean yellow. Their high end rules
    were all available in white. You'll find them on eBay, but expect to pay
    more because they're less common.
    
    As far as I know, Pickett trig scales were always marked in decimal degrees.
    
    On the following simulator you can use a (white!) Pickett N3 to work
    Gary LaPook's sight reduction example. Just drag the slide and cursor to
    make the settings. The only difference is that where he says to "line
    up" the S and D scales (bring their left and right indices into
    coincidence), you use C and D.
    
    http://www.antiquark.com/sliderule/sim/n3t/virtual-n3-t.html
    (The virtual slide rule requires that Javascript be enabled. After the
    page loads, it's self-sufficient, requiring no Internet connection.)
    
    Note that Gary's azimuth computation has a mistake. The message text
    says to set the cursor to cos 14°, but the picture and the final result 
    indicate it was set at cos 20° instead.
    
    
    
    Hein Bodahl wrote:
    > The Faber Castell 2/83, or even better the FB 2/83N Novo Duplex, is by
    > some said to be the best ever made. It is a desktop model of double
    > length. Unfortunatly that makes it sensitive to temperature changes (or
    > so "they" say).
    
    The famous Novo-Duplex, the so-called "ultimate slide rule", is dear to
    collectors. But I wonder how many of these just sit in display cases.
    They are so collectible, I'd hesitate to put one to work at home, never
    mind take it to sea on a small craft.
    
    Recently I bought a Faber-Castell 63/82, which has several of the same
    features:
    http://www.sliderulemuseum.com/Faber/P030_Faber-Castell_63-82_Biplex.jpg
    
    It looks impressive, but in actual use the 63/82 is cluttered and
    gimmicky. Those auxiliary hairlines are the worst part. They're hardly
    ever useful, and all those extra lines make it hard to read the scales
    quickly. And the slide has too much friction and stick slip. Its feel is
    the worst of any of my plastic rules.
    
    To be fair, I grew up with American slide rules. Fancy features like
    extra hairlines, Pythagoras scales, etc. have never been popular here.
    
    Not that we always know better. One ridiculous practice, common on
    American rules, is to chop off all scales to exactly the same length as
    C and D. Look at the left end of ST in that N3 simulator. Wouldn't it
    make sense to carry the scale down to .56°? The K+E 4080 family has the 
    same problem.
    
    As the picture of the Faber-Castell 63/82 shows, German makers often
    extend such scales a little to end them at a sensible graduation.
    
    
    nsg21---.com wrote:
    > British brand UNIQUE offered several sliderules of cheap 
    construction, but
    > interesting scale layouts. Among them was so called "Unqiue 
    navigational". In
    > addition to normal log scales it featured sine and tangent scales 
    located both
    > on slide rule body AND slide. Allegedly this would make certain trig
    > calculations easy.
    
    That's true. For example, to compute sin A sin B on a rule with trig
    scales on the slide only:
    
    1. Align the indices, i.e., center the slide so the C and D scales coincide.
    
    2. Set hairline to A on scale S.
    
    3. Pull C index under the hairline.
    
    4. Set hairline to B on scale S.
    
    5. Read product on D at hairline.
    
    But with trig scales duplicated on slide and body, step 1 is unnecessary
    if you use the S scale on the body for step 2.
    
    -- 
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