Slide Rules: Keuffel & Esser vs. Hemmi & Post Versalog

Рет қаралды 1,130

4 жыл бұрын

A comparison of slide rules from 2 of the major manufacturers in the mid 20th century
#KeuffelEsser #HemmiPost #SlideRules
Thumbnail Credit: Francis Fletcher

Пікірлер: 8

@va2wlt 3 жыл бұрын

To do squares, you inverse the procedure. You go from the R1/R2 scales to D. It's actually easier with the Versalog than with A/B scales because you don't have to decide which decade (left or right) the result needs to be.

@RobertResearchRadios 3 жыл бұрын

Yeah, the claim at 13:12 about squares being harder is likely unfounded, though it may have been my opinion at the time since I hadn't done many squares with a versalog rule before. After reviewing squares with R1/R2 and D vs. squares with C/D and A/B they seem like the same difficulty to me. As far as square roots I definitely find the R1/R2 scales easier to work with because i see both results at the same time and can toss the one that looks wrong without having to manually check both decades on the A/B scales by moving the marker around.

@RonBeselt 3 жыл бұрын

I think the main draw back of R1R2 with no AB us that you can't pull down a sqrt value 'on the fly' in an equation like B. Same issue with K on the stators. Really hard to use them as accumulators. AB with CD really allow for more continuous calculation vs just lookup table values.

@jadenephrite Жыл бұрын

Thank you for your video. Regarding the Keuffel & Esser plastic slide rules such as your 4181-3, these were not made of Bakelite plastic; instead they were made from ABS plastic which is Acrylonitrile Butadiene Styrene. ABS is a more durable plastic that Bakelite which is made from phenol formaldehyde but tends to be brittle and prone to cracking. Regarding the LL scales which are on both of your two slide rules but you did not mention. These LL scales are known as Log Log scales which are very powerful and used to calculate the roots or the powers of numbers between 22,026 to 0.0000454. For your example of calculating the square root of 130, you would go to 130 on the LL3 Scale and multiply it to the 0.5th power (which is the same as its square root). The answer is 11.4018 which is located on the LL3 Scale. In other words, the LL scales can do more roots and more powers than the A, B, and K scales which can calculate square roots, cube roots or raise a number to its square or to its cube.

@RobertResearchRadios Жыл бұрын

I'm going to have to read up on these scales. :) Thanks for sharing.

@jadenephrite Жыл бұрын

@@RobertResearchRadios The LL scales known as Log Log scales are typically based on Natural Logarithms and utilize Euler's Number "e". The LL Scales can be used to calculate the roots or the powers of numbers ranging from e^-10 = 0.000045 up to e^10 = 22,026. On the other hand, the L scale which is based on Common Logarithms can be used to find the mantissa of numbers from 1 to 10.