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Correct use of washers
Thinking about it - 1/4/09 at 08:41 PM

Stupid question but what is the correct use for washers?
Should all nuts and bolts use washers?
Under the nut or nut and bolt?
No washers at all.
Flat, star, spring? Where to use what.

flak monkey - 1/4/09 at 08:45 PM

Depends what you are doing.

Washer should go under the bit which you turn to tighten the fastener, so could be under the nut or bolt depending.

Flat washers for all normal joints.

Spring washers are evil and should all be destroyed.

Star washers, much the same as spring washers, but good on soft material such as aluminium.

If you are worried about it coming undone use a properly torqued nyloc. Or threadlock in cases where there are no nuts. Beware some studlock is incredibly strong and more trouble than its worth. In most cases, a properly torqued bolt should never come undone (think conrod bolts, flywheel bolts etc).

David

Thinking about it - 1/4/09 at 08:50 PM

General question all applications. Quite right what you say about the correctly torqued bolts. I hope anyway, just done mine.

greggors84 - 1/4/09 at 08:57 PM

Unless your really worried about weight use a washer the bolt side and nut side as your likely to get movement both ends when tightening.

Flat washers come with one side with a radiused edge, this should face the material being tightened on to. Wont be a problem in low torque applications.

If your worried about it coming lose as said use a nyloc and the right torque and you will be fine. You may find when things wear in like bushes or powercoating the bolts will seem loose. They are most likely as you tightened them just give them a nip up.

Torque seal can be used if your really worried, just blob some between the nut and end of the bolt and it will break if they move.

matt_claydon - 1/4/09 at 09:03 PM

http://www.straightdope.com/columns/read/1713/whats-the-purpose-of-washers-the-round-metal-things

Simon - 1/4/09 at 09:31 PM

Someone (maybe hicost or Jon Ison though I 'm probably wrong) posted a vid or suchlike on here a few years(?) back about washers, locking washers and nylocs coming undone (during extreme tests) and showing another thing that didn't.

Just though you'd like to be reminded

ATB

Simon

gazza285 - 2/4/09 at 05:21 AM

Probably Nordlocks.

designer - 2/4/09 at 07:49 AM

As a general rule. ALWAYS use a washer under ALL nuts and bolt heads, unless specified.

They spread the loads and stop gauling of the fitting.

Never use spring washers anywhere

Daddylonglegs - 2/4/09 at 08:27 AM

quote:
Originally posted by designer
.....Never use spring washers anywhere


Any particular reason?

Just curious

scudderfish - 2/4/09 at 08:31 AM

I'll bite. What's wrong with spring washers then?

flak monkey - 2/4/09 at 09:24 AM

Spring washers tend to spread if a bolt is done up too tight, they can then eject themselves from under the head of the bolt leaving it very loose....

They are ok on non critical fasteners or ones that arent done up very tight. Otherwise, avoid them.

irvined - 2/4/09 at 10:10 AM

Carrol smith has a great book on fasteners, it covers nuts, bolts, aviation fittings, pipes, tubes, clips and just about anything that ever falls off.

(Although expect some anorac jokes if your mates catch you reading it.)

David Jenkins - 2/4/09 at 11:23 AM

quote:
Originally posted by irvined
Carrol smith has a great book on fasteners, it covers nuts, bolts, aviation fittings, pipes, tubes, clips and just about anything that ever falls off.


Obscure factiod: Murphy (of Murphy's Law fame - "Anything that can go wrong, will do so at the most inconvenient moment" ) is Carrol Smith's father-in-law!

One thing that he says is that you should use HT washers under HT nuts and bolts - if you don't they can squash under compression and allow the fastener to become loose. Seems sensible advice - but when's the last time that you saw HT washers on sale? (I got mine as part of a package of aircraft-grade bolts, nuts and washers).

mad4x4 - 2/4/09 at 11:48 AM

quote:
Originally posted by flak monkey
Spring washers tend to spread if a bolt is done up too tight, they can then eject themselves from under the head of the bolt leaving it very loose....

They are ok on non critical fasteners or ones that arent done up very tight. Otherwise, avoid them.


So.. (ducking for cover) on that bases explain why some vehicles use spring washers on Flywheels and Heads....
If they are that crap them surely nowone would use them.

Are you sure you were usig a metric spring washer of the right size. I have seen this happen if you use an 10 spring washer on an M8 bolt.

MikeRJ - 2/4/09 at 12:01 PM

quote:
Originally posted by mad4x4
So.. (ducking for cover) on that bases explain why some vehicles use spring washers on Flywheels and Heads....


What engine uses spring washers on the head bolts? I've never seen one that does.

Bolts to attach clutch covers to flywheels tend not to to torqued particularly high, so spring washers could be useful in this situation. However, you won't find many spring washers on a modern car compared to older ones.

[Edited on 2/4/09 by MikeRJ]

iank - 2/4/09 at 12:56 PM

quote:
Originally posted by irvined
Carrol smith has a great book on fasteners, it covers nuts, bolts, aviation fittings, pipes, tubes, clips and just about anything that ever falls off.

(Although expect some anorac jokes if your mates catch you reading it.)


Even more so if one of them knows that many people (based on the pattern from his other book titles) refer to it as "Screw to Win"

owelly - 5/4/09 at 07:50 PM

My engines at work have 16 cylinder heads. Each cylinder head has two exhaust outlets. Each outlet has four bolts. Each exhaust has nine joints. Each joint has 4 bolts. Then each exhaust fastens to the turbos with ten studs. They all have spring washers. I'm not too sure a nylock would last too long at 600degrees c.................