The L9® Fastening System is designed for use in high stress, severe service environments. The highest mechanical strength off-the-shelf fastening system available, its special features control torque-tension characteristics to develop high clamp loads when using properly controlled tightening methods. Specially designed features include:

• Thicker than standard bolt head adds wrenching surface

• Washer face eliminates corner drag

• Radius under bolt head adds strength

• Countersunk washer inside diameter centers the washer against the bolt head bearing surface during tightening

• UNR Radiused root bolt thread increases fatigue resistance by reducing the notch effect of conventional UN threads.

 • UNR Thread radius is maintained into the thread run-out at the junction of thread to shank

• Smooth washer bearing surfaces distribute loads uniformly and reduce brinneling.

• Plated finish assists torquing

• Chamfers eliminate corner drag

• Thicker than standard nut side walls facilitate wrenching

• Heat treating helps prevent splitting and stripping