Starrett #657A Magnetic Base w/ Swivel Post

Description

Starrett 657A Magnetic Base Indicator Holder with Swivel Post Assembly
The swivel post assembly on these holders provides universal adjustment in both horizontal and vertical planes. Available with inch or millimeter Dial Test or Back-Plunger Indicators, they save time in shop set-up and other inspection jobs.
For use with all Test, Back-Plunger, AGD, Dial and Miniature-Dial Indicators. Also accommodates similar indicators of other manufacturers.
Powerful, permanent magnetic base holds firmly to steel or iron surfaces – horizontally, vertically, upside-down. Push-button turns magnetic force on or off for quick, one-hand set-up and take-down. V-step adapts base to horizontal or vertical arbors and chucks. There is an extra 1/4-20 NC tapped hole in side of base for indicator mounting post. Three precision ground magnetic contact surfaces (plus V-step). Black wrinkle finish on non-working surfaces.
Features
657P Magnetic Base is 1-15/16" x 1-5/8" x 1-7/8" (50 x 40 x 48mm) deep.
Swivel Cap Slot permits 90º post travel to horizontal position.
Post rotates 360º.
657F Indicator Swivel Post Assembly is 6-1/2" (165mm) high (less threaded end).
Fine-Adjusting Screw. Turn to zero set indicator.
Upper arm is 2" (50mm) long with a 5/16" (8mm) diameter and swings more than 180º; friction joint holds it in position.
7/32" (5.5mm) diameter step, 1/2" (13mm) long.