Cross Manufacturing has announced an extension of its Spiralock range of self-locking wire thread inserts, which are now available in sizes down to M3 and 4 x 40 UNC. Manufactured from 18/8 stainless steel in the hard drawn condition, Spiralock inserts provide internal threads to suit standard bolts in Metric and Unified sizes.
The introduction of smaller sizes has been driven by applications involving miniature light alloy castings in industries including aviation and communications, where maximum integrity and resistance to vibration are essential for safe and reliable operation.
Designed by Cross Manufacturing to maintain bolt tension under the most severe vibration conditions, Spiralock self-locking thread inserts utilise a thread form that radially centres the male member to the female member and compressively loads each engaged thread on the wedge ramp to ensure an even distribution of the bearing load on the entire wedge spiral. The result is the virtual elimination of the fatigue failures experienced with conventional thread forms due to a high stress concentration on the first engaged thread. Vibration tested under extreme conditions, Spiralock inserts have substantially out-performed all standard thread inserts, with analysis showing no loosening or fatigue during 1000 test cycles.