FILENAMES: drillpress_1.jpg drillpress_2.jpg DESCRIPTION: These are pictures of a digital tach for a drillpress. Posted by Terry May . The following description was provided: ================================================================= About a week ago there was a thread concerning digital tach readouts for machine tools. A Mr. Paul Dickman among others, described using an inexpensive bicycle speedometer for this purpose. I purchased one of the recommended Sigma BC800 speedo's from Cherry Creek Cyclery (on sale for $19.95) and programed the wheel diameter as described by Mr. Dickman. I checked the speed with a 60 cycle 1725 rpm motor and it was right on. I adapted this speedometer to my drill press which had been previously reto-fitted with a Surplus Center DC motor. I used the speed control that came with the motor and adjust the speed with a simple potentiometer knob. This is the "old" Surplus Center treadmill motor, I don't have any experience with the newer versions now in their catalog. The speedometer works by a magnetic sensing switch, I did not use the magnet that came with the speedometer, but inserted another cylindrically shaped magnet into the spindle aluminum pulley of the drillpress and epoxied it. Drillpress_1.jpg shows the sensor mounted on a wooden block and about 1/4" from the pulley rim. I'm very pleased with the setup, the motor works well under drill press loads and the digital speedometer seems to be very accurate. A note, the Sigma speedometer works to over 300 kilometers per hour so the speed range is aroung 3000 rpm, the motor on the drillpress will go higher than this, but I personally never need to exceed the 3000 rpm range of the readout. Terry May