Pickett & Eckel Model 500 Variations
(Click on images for details)
Model No. 500
1948

slide rule
slide rule
Magnesium body/slide.

White number on black circle used on CI scale.

Note scale labeled "LLI" on left and "LL1" on right.
Model No. 500
1950

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Model No. 500
1950

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Note: no mask numbers but otherwise identical to above.
Model No. 500
1951

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Note introduction of "<" for inverted scales and relabeling of LLn scales.
Model 500
1952

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First aluminum version.
Model 500-T
1954 ?

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Thin aluminum body.
Trig scales rearranged.

First version without serial number.

Model 500-T
1957 ?


Model 500-ES
1957 ?

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Grooved slide. Outside of rails still grooved for cursor.

Introduction of range values on LLn scale labels.

First version with slide tension springs.
Model 500-ES
1958

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Model 500-T
1959

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Inverse scales in red.

Model N500-T
1960-61


Model N500-ES
1960-61

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The first N500's still have LL0 and LL00 scales.

And where did the red ink go?
Model N500-T
1962

Model N500-ES
1962

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Introduction of -LLn and DI scales.

Range values added to trig scales.

Range values moved on right end scale labels.
Model N500-ES
1962

Grantham Electronics Schools

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slide rule

Model N-500-T
1962-63


Model N-500-ES
1962-63

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Introduction of wide convex lenses.

Model N-500-T
1963-64


Model N-500-ES
1963-64

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Model N-500-T
1964-?


Model N-500-ES
1964-?

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slide rule
Model N-500-ES
1964-?

Grantham Electronics Schools

slide rule
slide rule

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