By careful selection of the lubricants, AF coatings can be designed to meet specific applications.The coatings are permanently bonded to the metal surface and provide a lubricating film preventing direct metal to metal contact.The thread form has rounded roots and crests, the thread form is specified in BS 84: 1956.This thread form was superceded by the Unified thread in 1948 and then the metric thread form.The nut face coefficient of friction would be due to zinc plating contacting the joint surface finish.The Coneloc is an all metal prevailing torque type self-locking nut.
In some applications it is used to improve corrosion resistance to allow the parts to be subsequently dis-assembled Thirdly, it can provide a barrier to water penetration since the threads are sealed by use of the compound.
A chromate conversion coating is frequently applied to the surface to improve corrosion resistance.
Cadmium is not now frequently used because of the environmental and worker health problems associated with the coating process and should not be used in applications above 250C or when contact with food is possible. The collar of the nut is elliptical in cross section and it is this that provides the flexible locking element.
Aerotight is a registered trade mark of The Premier Screw and Repitition Co.
Ltd of Woodgate, Leicester, United Kingdom, LE3 5GJ.