- Joined
- Jul 12, 2015
- Messages
- 287
Rule #1, Slide rules need no batteries!
My first really good calculator was an HP35. Reverse polish is better in my opinion..........I miss it still.
Need help! I can’t find the Equal Sign.
Rule #1, Slide rules need no batteries!
My first really good calculator was an HP35. Reverse polish is better in my opinion..........I miss it still.
Back in the eighties, I designed a circular slide rule the would calculate the length of bar stock required to make a shoe for a horse, based on two measurements of the horse's hoof. My ex, who was a farrier, made and sold quite a few of these to other farriers.Took course in engineering curriculum - nomography - we learned how to construct the "on paper" calculators that you laid a ruler across and connected the quantities you had making the ruler cross another line with the quantity(ies) you wished. Miles per gallon calculators are an easy example. Design of pressure vessels is a complicated one. Any equation can be represented with such a chart. It was a very informative course taught by an excellent professor and it explained a whole lot about how the world works and how we approximate it to our best benefit. Now we use spreadsheets and apps to generate these types of short cuts.
I used five place log tables a lot on college when we needed more precision than the slide rule would provide. One can appreciate the seven place tables when you realize that every additional place multiplies the number of pages of tables by ten. My five place tables in the CRC Math Handbook require 20 pages.A further more accurate slide rule was the drum slide rule used by a lot of Drawing offices. These had the logarithmic scales on the outside of a drum which could have a scale length of 500 " as opposed to the 10" normal straight linear type. Sure was a lot quicker (though not as accurate) as using log / anti-log tables ( 7 fig. tables in the D.O. !)
Happy days !