When forklift truck leaf chain is in its original condition, the rivet pins and articulating link apertures are almost perfectly cylindrical and, more typically in good quality leaf chains, they have very good surface finishes.
This desirable condition produces leaf chain with excellent bearing properties that give rise to smooth, quiet and efficient operation.
As the forklift truck chain inevitably wears, however, these conditions deteriorate with the leaf chain rivet pins wearing (known as Galling) where they become castellated as shown in the picture above.
As a forklift truck chain wears, the apertures in the linkplates also become elongated as shown the above picture of a rusty leaf chain linkplate.
The vast majority of leaf chain rivet pins are manufactured with a case hardened outer surface. It is generally accepted that a 3 per cent worn leaf chain will lose approximately 18 per cent of its tensile strength.
As forklift truck chain pins continue to wear the castellations become so deep that the case hardening of the leaf chain rivet pin will be completely destroyed. Once this case hardened surface is worn away the leaf chain will rapidly wear and become a lot weaker and therefore very dangerous.
It is for this reason that there is a need to limit the amount of leaf chain wear that will be acceptable.
The FB professional chain wear gauge (CWG) is a precision tool that can accurately measure the amount of wear in forklift truck chain/ leaf chain.
The instructions that accompany this leaf chain wear gauge state that at 2 per cent wear the leaf chain will need careful monitoring for continued use.
At a level of 3 per cent wear the leaf chain must be removed from service for the safety of all concerned.