Lock washers

[pete black]

I am sure this has been discussed before but; are lock washers reusable? Thanks.

 

[old]

If you have the split ones yes as long as the split end of it still has the spring tension to it but if the ends are flat to each other it is no good

 

[jeffcat]

Another thing. There ARE left hand lock washers! Have some on the Gravely rotary mower.

 

[Janicholson]

A study was done by Gary Nut and Bolt in the 1960s. Short answer. Do not use them. Long answer: Often they are used with flat washers under them. Making the locking feature totally irrelevant. (think about it) they often crack in half and fall out. (real handy for keeping things together, have you ever taken a nut off and had the lock washer fall apart? They require the nut and the base metal to be soft enough to be nicked into by the washer's split and edged surface. Some clamped surfaces and nuts actually are soft enough most aren't. The torquing of the nut is compromised by the deflection of the washer. The point contact of the split area focuses stress risers in the base metal and the nut.
If you want a nut to stay put, use a castellated nut and cotter pin. or appropriate locktite. Deformed nuts are OK, but a one time one way trip to new each time. Jim.

 

[Hobo,NC]

Whut he said... But depends on were you use them... I am guilty of using a lock washer with a flat-washer... Just depends on the application...

 

[markiz41]

These are

http://www.nord-lock.com/nord-lock/wedge-locking/washers/introduction/
NORD LOCK

 

[DR. EVIL]

I remember the day the 8 or 12 or 16 Mellowes lock washers on the rim clamp bolts on every tire/rim mounted at FARMALL started cracking, breaking, and falling out when tightened in the tire room. Rear tires were about the last thing put on a tractor. Ended up shutting the finish assembly line and eventually the plant down. One of the very few times, like 2 or 3 times, I remember a supplier quality problem shutting the place down. Needless to say, Mellowes air chartered at their expense, parts from a different production lot in to get us going again ASAP. I never actually heard what the cause of the failure was, I had my own parts issues and suppliers to deal with. It only happened once. Mellowes is now part of ITW Shakeproof Group. If I had to make an educated guess, I bet that batch of washers got heat-treated too hard, or more correctly, didn't get drawn enough.

In the long term scheme of things, lock washers do not crack/break all that often, even when over-tightened dozens and dozens of times. Normally rust is needed to finally cause them to crack and break, known as Stress Corrosion cracking. I have drilled holes in nuts tightened on bolts and installed cotter keys, used torque retention nuts, deformed style, the nylon insert style I find has the least holding power, a quick coat of paint holds threaded fasteners more securely.

 

[pete black]

Thanks, enjoyed your reply.

 

[dr sportster]

In this book which came out some time ago it claims these washers are ineffective . An obsolete idea.
Race car hardware

 

[CGID]

How about using split locks and flat washers when bolting wood together? The flat washer to spread the clamping stress out and the split lock to provide some spring tension to make up for shrinkage.

 

[MeanGene1]

Good for making a GMC out of a Chebbie

 

[Moonlite37]

I read that Henry Ford did not believe in using them. Used fine nuts. Personally I like to use double nuts if space allows

 

[Hobo,NC]

(quoted from post at 07:42:55 09/10/17) How about using split locks and flat washers when bolting wood together? The flat washer to spread the clamping stress out and the split lock to provide some spring tension to make up for shrinkage.

OK it may help keep your supper table are chairs legs tighter longer but I don't think there is a long term fix....

 

[Shoprat]

Take a look at this product, I know the guy that owns this company.

http://fasteners.sherex.com/category/disc-lock-wedge-locking-washers

 

[kevinthefixer]

I'm a believer in cone washers or wave washers. They have a bit of spring tension but do not chew up the bolt/nut/surface. Good for sheet metal, or aluminum cases where a split-lock will gouge badly.

 

[Russ from MN]

I'm a firm believer in nylock lock nuts, they don't damage the bolt threads.

 

[Janicholson]

Use Belleville Washers (2 of them at least) for that. Locks push crooked. Jim

 

[showcrop]

If they dig in and don't move between assembly and disassembly and there is no rust, they won't take any wear. so they are good for another use. Any movement or rust will reduce the hold ability. Having a flat washer underneath won't affect the locking ability simply because the flat washer has so much surface area friction is very high if the nut is tight.