Loga

I've made a few models of Loga cylindrical slide rules. But I've yet to figure a way to fashion the prominent little ovoid handles originally used to turn the sliding "cage", so they're not really replicas. I'm also hampered by never having seen one in real life, just pictures on the web.

As with my other models, Wayne Harrison provided the scales. In fact, he build a scale-generator command-line app. It takes a "config" file listing size and style parameters and generates a Postscript file that can be turned into a PDF. The user can control how the tic-marks are arranged in different ranges of the log scale, the fonts of the numbers, placement to optional tic-marks of integer reciprocals and more. This allowed me to make Logas in a variety of sizes, from handheld to a monster with a 50 foot scale.