For Sale, SPI BIG Tapping Head, Model Number SPI 76-010-8.
Fits the conventional R8 spindle in a Bridgeport Series 1.
Used in Good Condition. $175.
5/16" to 3/4" (Holds larger taps than the Tapmatic.).
In the picture with 2 tapping heads, the SPI is on the left. It's about twice as big and 4 times heavier than the Tapmatic.
SPI = Swiss Precision Instruments.