HOW DOES IT WORK?

Self-Lock™ is an engineered wedge ramp at the root of the internal thread that only engages when the joint starts to build clamp load during tightening. At that point, the crest of the standard external threads draws tightly against the wedge ramp, eliminating all radial clearance and creating a continuous spiral line of contact between the internal and external threads.

Standard 60° Thread

Self-Lock™ Thread

The first two threads on a conventional fastener (left) may carry as much as 75% of the load, while load on the other threads is drastically reduced. A standard 60-degree thread form leaves a radial gap between the crest of the male and female threads. This makes the nut-bolt assembly susceptible to transverse motion and loosening under vibrational loads. Additionally, when the first one or two threads carry most of the axial tension load, highly concentrated contact stresses can cause fatigue and the probability for shear and thread stripping, especially when bolts thread into soft metals. The EMUGE Self-Lock™ profile eliminates the radial gap and creates a continuous-spiral-line of contact along the whole thread engagement and more evenly distributes the concentration of tightening force. Calculations amount to a share of 17% of total load on the first thread and an amazing 12.5% even on the last engaged thread.

THREAD GAGING

To avoid potential assembly problems due to dimensional variations, we highly recommend inspecting EMUGE Self-Lock™ threads exclusively with EMUGE Self-Lock™ gages to ensure the highest and most constant locking power. We recommend using an EMUGE two-piece gage system which corresponds to the normal combination of Go and No-Go. These gages are perfectly sufficient for the gaging of the EMUGE Self-Lock™ thread, provided that the Self- Lock threads were produced with a true-to-profile EMUGE tap.