Print In Place Ringed Slide Rule

thingiverse

This should print well without support using a 0.4 mm nozzle and 0.2 mm layer height. Shiny opaque "silk" filament may help with reading the markings. Note: Some slicers may need an adjustment for the minimum feature size. For PrusaSlicer, the setting is called "Slice gap closing radius" which I had set to 0.0005 mm. Some youtubers made videos about using a circular slide rule. Mathologer: https://www.youtube.com/watch?v=ZIQQvxSXLhI&t=195s Professor Herning https://www.youtube.com/watch?v=UKX7HQeFaNI The ring slide rule works the same way except it's read on the side instead of on top. And this model does not have an index (a line that shows how the numbers line up). A finger or other pointing device can be used as a guide for reading numbers. The constants on the ring are: c = sqrt(4/pi) multiply this by the square root of an area to find the diameter of a circle with that volume. e = 2.72... which is the base of the natural logarithm. pi = 3.14... which is the ratio of the circumference of a circle over its diameter. Dh = sqrt(2*radius of earth in meters) Multiply this times the squareoot of your height above water to approximate the horizon distance. Phi = 2/(1+sqrt(5)). The inverse of the golden ratio. Also very close to the number of miles per km which can be used for conversions. Note: A slide rule helps with finding roots which are halfway between the value and 1. Keep in mind that there are two ways around the circle. So, a string that goes from 1 to a number may be folded in half to find the root. For printing in place, the base with a line cut between the inside and outside of the ring should attach to the print bed. The inner radius is set to 80 mm, you may scale it up or down to fit different wrist sizes. There is a slight asymmetry between the top and bottom marks. The bottom marks (the top part as used after printing) were clipped, and the gap shifted to help with printing. The models appear upside-down because that is the orientation for printing on the most common printers at the time of publication. The stl that starts with LaurentDespeyroux is the recommended print to start with. It's named after the designer of labels and scales with mid unit markings. The stl that starts with Robust which is a sturdier version that's less likely come apart. The stl that starts with Tight has a gap of 0.25 mm instead of 0.4 mm to give a more precise fit, though it may fuse the parts on printers that work with the generous 0.4 mm gap. The stl that starts with cutoutView is a model with a portion removed to show the sliding mechanism. The stl that starts with TrigBowl prints a bowl with additional scales for log and sin. Also, it prints right-side up. The stl that starts with Large prints the simple two ring design but large, with an outer diameter of 158mm, that shows how size increase accuracy for slide rules when other factors are the same. stl files ending with "30ths" have the intervals between some numbers divided into thirtieths. There is an openSCAD file which offers more parameters for sizing and tolerance. It is zipped because it doesn't play well with the thingiverse customizer app. It should work well with the latest version of openSCAD. https://openscad.org/ There is a joy to pulling functional print in place models with moving parts from the printer.