Working on my 3 position semaphore project, and recall reading an article I think by Circuitron on how to add a mechanical stop to one side of case to overcome the Tortoise internal switch deadband so the blade will stop reliably on yellow. It describes making motor run to center from one end, mark the center line, mark it then run from other way to center mark it, and then calculate differences and glue a plastic block to create a "false" stop stall point so motor now always stops dead center.
My bad is I think I deleted it, thinking I had printed it off and put in my RR "bible". 
Anyone recall what I am writing about? I searched Circuitron application notes and catalog to no avail.
