FILENAMES: tachfnt.jpg tachzero.jpg tach0090.jpg tach3000.jpg tachsenb.jpg tachsenr.jpg DESCRIPTION: These are pictures showing an electronic tachometer for machines. Posted by Dan Mauch . Dan provided the following description: ----------------------------------------------------------------------- Here is a way to finally know what your spindle speed is on your variable speed type machine such as the Sherline, Grizzly, Maxnc and for other machines with single or dual motors. No more trying to figure out the lousy charts on imported machines. The attached pictures pretty well explain everything. Enjoy Dan Tachometers for Variable Speed Machines. I have a variety of computer controlled machines in my shop. I designed and modified a Sherline Mill for CNC but one problem I noticed was with the Sherline variable speed spindle motor controller was that there was really no way to tell how fast the spindle was turning. The speed control dial is marked slow and fast. So I decided to add an optical tachometer. The Tachometer consists of a kit (see www.seanet.com/~dmauch) that includes a printed circuit board, a preprogrammed PIC chip a multiplexed LED 4 digit display and a optical sensor. It is easy to put together. The kit will also work with dual sensors on machines like the Smithy, and Shoptask with dual lathe/mill motors or other variable speed machines requiring a single sensor like the Grizzly mini mill or Maxnc mills. Additionally, it should work on all the other mill/lathes and drill presses. The attached pictures show the tachometer in operation. It can be set up to use 2, 4, or 8 reflective strips or if you have a shiny pulley like the Sherline you can use black tape. Use more strips for better low speed resolution and fewer if you prefer higher speeds. I have found that 4 strips work best from 50 RPM to 5000 RPM. We have Hans Wedemeyer to thank for discovering the new mutiplexed LED display and for providing the circuit diagram and program for the PIC chip.