Strain Gage Installation Tool

Abstract

This paper describes the development of a tool designed to spot weld Ailtech strain gages to the inside surface of small diameter tubing. Fundamental spot welding techniques are discussed with emphasis placed upon the adaptations that were necessary to attach a gage that was neither visually nor physically accessible to the installer. A special electrode was made that enables a pair of welds to be made simultaneously, one on either side of the strain tube. The installation tool described has been used successfully to spot weld four strain gages spaced 90 degrees (1.57 radians) apart to the inside surface of 0.552 inch (14.02 millimeter) diameter tubing to depths of 26 inches (660 millimeters).