Pickett N3-ES & N3P-ES Power Log Exponential
The model N3-ES was produced in the United States from 1960 until 1975. Fabricated with aluminum this linear slide rule is coated with Pickett's distinctive "eye saver" yellow coloring. The was all plastic screwed to plastic ends, and hold with metallic end posts. It was made in two sizes: the N3-ES (12 inches long - 10 inches scales) and the pocket size N3P-ES (7.5 inches long - 5 inches scales).
Designed with 32 scales is one of the most powerful slide rules ever fabricated for Science and Engineering. It has one scale more than the Aristo 0972 Hyperbolog and the Faber Castell 2/83N, but it is not the slide rule with the more scales, this honor corresponds to the Flying Fish 1003 Vector with 34 scales!
The scales on the N3 family are: √#1, √#2, K, A [B, ST, S/Cos, T1, T2, CI, C] D, DI, 3√#1, 3√# 2, 3√#3 on the front face, and LL0+0.001/-0.001, LL1+0.01/-0.01, DF [ CF, CIF, Ln, L, CI, C ] D, LL2+0.1/-0.1, LL3+1.0/-1.0 on the back face. Same as is ancestor the Model 3, it has long scales to calculate accurate cubic roots (split in three portions), and square roots (split in two portions). Also the eight Log-Log scales labeled labeled now with the standard LL#, give also a precision up to four decimals, but these are now conveniently paired on four lines to save space on the rule. The model N3 does not have a whole reference table of the significant digits for the √#, 3√#, and LL# scales, as the Model 3, but only some useful annotations at the end of these scales.
I consider, according to the logo on the rules, that the specimens in this collection were fabricated between 1964-1967:
For training purposes, this model was fabricated in a 7 feet long plywood version. I have one of these specimens hanging in my classroom:
Here a link to a great simulator of the N3 rule:
http://www.antiquark.com/sliderule/sim/n3t/virtual-n3-t.html
With a N3 model it is possible to solve with a precision of two or three digits the next numerical problems:
SlideRulePractice-2.pdfNext is the scan of the User Manuals for this model (Courtesy of the ISRM and my own) explaining the use of the different scales in this rule:
M51_Pickett_HowToUseTrigSlideRules_1960.pdfM76_Pickett_HowToUseLogLogSR_1953.pdfPickett-DualBase-Exponential-Ln-LScales.pdfI wanted to compare the first Model 3 - 1947 design, with the last Model N3 - 1959 design. Both models have the same scales but the distribution of these changed. Also the original design had no grouped scales and a reference table, in the last one some scales were grouped and there were no reference table. Here are together to compare:
