Introduction
SunLock uses machine screws (also called bolts), washers and nuts in a variety of locations. This technical bulletin describes how to prevent a fastener from loosening. (Carroll Smith’s nuts, bolts, fasteners and plumbing handbook, 1990, page 116. )
Lock washers
A serrated or star washer can be effective when machine screws bear onto a relatively soft surface such as aluminium.
Helical Spring Washers
Helical spring washers are ineffective, as the spring force created by the washer is far less than the axial tension in the bolt. They effectively act as a flat washer.
Nyloc nuts
Nylok nuts create friction directly between the nut and the bolt, which prevents them from rotating and loosening. These are effective.
Durlock nuts
Durlock nuts have a serrated surface on the lower face, which is easier to tighten than to loosen. These are effective.
Reference
Barrett (1990) Fastener Design Manual, NASA
Smith (1990) Carroll Smith’s nuts, bolts, fasteners and plumbing handbook, Motorbooks International
Tomotsugu (2008) Bolted joint engineering: Fundamentals and Applications, Beuth
For Further information
For further information contact Sunlock on 1300 655 554 or order@sunlock.com.au.