Metrology indexer (4-position)

INTRODUCTION
This document describes the functionality of the fixture, and the basic dimensions.  Useful data (unit conversion), materials and complete manufacturing drawings also included in appendix.

MAIN SECTION
The indexer is composed from the indexer body, the shaft, the pinch knob, the detent and the compression spring. The shaft mates with the indexer body. The shaft’s abutment fixes axial movement in one direction and in the other is secured in place by the knob. The knob is assembled at one end of the shaft whilst the other is free for mounting an auxiliary clamping fixture (depends on part).  A set screw is locking knob with the indexer shaft. The shaft has four dimples at ninety degrees between them. A detent with a spherical end is constantly forced by a compression spring against the shaft, inside the dimple. Its time the shaft rotates (through pinch knob) the detent locks it through the dimples, having this way four indexing positions.