I noticed something strange about the speed chart under the top belt cover. It represented a 5 tier pulley setup, but the drill actually has a 4 tier pulley. That made it impossible for me to determine the actual speed of the drill. I could still judge the relative speed, but not the actual speed and this really bugged me.
I needed a method to measure the speed of my drill press. I have an oscilloscope and I realized with a little rigging… I could use it to measure the speed of my drill.
I repeated the measurements for the entire range of the belts on the spindles. Then I graphed the results. It’s interesting to see how non-linear the graph is. I stuck the new chart on my drill and now I have a very exact reference for my drill speeds.