How to Tighten Lock Washers

Tightening a lock washer the correct way is very important, since doing so means whatever is supposed to be locked by the lock washer will be secure. Not doing so can be hazardous to you or others if a nut backs off and causes an accident because it wasn't locked into place. Most lock washers work on one of two principles: compression, and an interlock or a bite. Either way, or even if both principles are used, using the correct lock washer the correct way is important in keeping nuts and hardware from loosening and possibly causing damage.

Instructions

1. Tighten a fore nut. A fore nut is the closest nut to the contact surface or bolt head, or the first nut used when two or more nuts are used together to secure a joint. Slip a split lock washer onto the bolt behind the fore nut. The slip lock washer is designed to use both compression and an anti-rotation bite to lock a nut in place. Tighten the aft nut onto the lock washer, tightening it just enough so as to cause the slip lock washer to use its designed spring force onto the fore nut and its slip to bite into the bolt. The aft nut is the second nut used in tandem with the lock washer and the first nut.

2. Fit a star-shaped, or star lock, washer between parts that it's supposed to interlock, particularly a nut or bolt and a working surface. Tighten a star-shaped lock washer so that the tines of the star dig into the mating surface, helping lock hardware together by means of both compression and interlock.

3. Fit the hole of the tab lock washer onto a threaded bolt. Tighten the lock washer and bend its tabs over a nut, or into the groove of the bolt, or a hole in the working surface into which it's meant to lock. A tab lock washer is a small, thin (metal) plate (typically disc-shaped) that has one or more "tabs" that protrude (typically externally) from its center.

4. Fit a ribbed lock washer wherever you need to secure a screw connection. Tighten the ribbed lock washer onto the contact surface, with the ribs against the contact surface.

Tips & Warnings

• Follow any written assembly instructions to whatever you are assembling, paying attention to when and where a lock washer is used. Follow drawn diagrams for using lock washers, and in the order they're to be used with nuts and bolts.

• If a fitting calls for the use of a lock washer, even a particular lock washer, use it. Not doing so can result in a loose assembly that can be damaging or even harmful to life and limb.

References

• How Do Lockwashers Work
• Various Types of Washers
• Lock Washer Patent Diagram and Abstract