Lock Nuts - Metric Fine Pitch Left Hand

A left hand thread is the terms used for a thread where the nut tightens in the opposite direction to normal. It is commonly used on items that rotate in a manner that could cause a normal right handed nut to loosen, for a example the pedal of a bicycle on the left hand side.

Metric fine thread is a common thread, often found on machine screws. More threads per axial distance (length along the fastener) than metric coarse. A fine thread is known to be stronger than a coarse thread.