The MachTach is a machine tachometer which is used to display the speed of any machine tool. The MachTach is capable of displaying revolutions per minute (RPM) or surface feet per minute (SFM). The MachTach can be built in two sizes using the same parts and it can be installed inside your machine tool or in it's own enclosure.
This site has MachTach documentation, photos, and video links. If you would like to build a MachTach, there's a page with information on how to buy MachTach kits or parts.
Displays RPMs and Surface Feet per Minute (SFM)
Metric Version displays Surface Meters per Minute (SMM)
& has mm diameter entry
NEW - We just published Version 2.1 of the User's Guide. The new guide finally has page numbers! Somehow we didn't notice they were missing.