Strobe disc tachometer for lathe or other spinny thing

I have a 1958 Craftsman lathe that I converted to variable speed with a DC motor. Wanting to know it's speed range, I decided to go old school with a disc tachometer. I used discs calibrated for 60hz and they work fine with shop fluorescents. See the video for more details. Included below is a disc pattern I made and is free to use. The youtube video page has a link to the full size graphic.

The knocking sound was a loose set screw.
http://www.youtube.com/watch?v=-SefCxuU9-Q


http://i.imgur.com/cda4Kozl.jpg

http://i.imgur.com/1aX6gx7l.jpg

Thanks wormil! I've added your Strobe Disc Tachometer to our Measuring and Marking category, as well as to your builder page: wormil's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="/strobe-disc-tachometer"><img src="/uploads/64560/strobe-disc-tachometer.jpeg" alt="Strobe Disc Tachometer" /></a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="/strobe-disc-tachometer">Strobe Disc Tachometer</a> <span> by <a href="/builder/wormil">wormil</a></span> </div> <div class="tags"> tags: <a href="/tag/lathe">lathe</a>, <a href="/tag/tach">tach</a>, <a href="/tag/disc">disc</a> </div> </div> </div> </div>