I successfully made the crank shortener (for an exercise bike) and saved at least $100. Here it is in use:



Then I saw that I needed special pedals that came in 9/16" so I consulted this chart to help my search for a fine thread 9/16" nut. Based on that, I thought I needed to look for 18 TPI. Turns out it's not fine enough, so I need different nuts or any of four or five work-arounds. I may order these and their left hand thread equivalents, or I can get a used crank arm on Craigslist for $10 and cut off the threads to use as nuts, or get a 1/2" to 9/16" adapter (I already have nuts for 1/2" pedals as seen in the video). I can also tap my own. There's nothing to worry about.