Stress Indicators, Inc. Expands Size Range

One-and-a-Half Inch Diameter Bolts Converted into SmartBolts

Stress Indicators, Inc. recently produced the largest diameter SmartBolts ever, 1-1/2×8” Grade 8 hex head cap screws for use in a Florida phosphate mining application.   The multinational mining company uses these SmartBolts on their industrial slurry pumps to reduce inspection and maintenance time, and to reduce unscheduled downtime.




Using the SmartBolts Visual Indication System™ and ordinary tools, technicians can ensure that critical pump bolts are installed with the required bolt tension.  SmartBolts measure only tension, so variable friction factors that can make torque measurement an inaccurate tightening method are removed from the picture.  Proper clamp force on the bolted joint ensures operational integrity and supports continuous uptime of the critical pumps.

Daily inspection is a quick, no-touch procedure because SmartBolts Visual Indication System continuously displays the level of tension on the bolt.  Without even picking up a wrench, technicians can visually verify that the bolts are tight and the system is ready to put into service.  If a SmartBolt should loosen in service, the eye-catching red loose indication instantly warns any observer that action is required to re-tighten that bolt.

Stress Indicators, Inc. is a manufacturing and engineering company based in Gaithersburg, Maryland. The company manufactures Direct Tension Indicating (DTI) SmartBolts, which can range in diameter sizes from 7/16” up to 1-1/2”.