Page 1 of 1
Spring washers dont lock?
Posted: Sat Feb 28, 2009 1:27 am
by Dooley
Ive read a Nasa manual lately that stated that a spring washer acts as a flat washer when a bolt is tightened up and does nothing to lock the bolt. Was wondering if anyone had any opinion on this?
Why are they still used then if a flat washer does the same job?
Posted: Sat Feb 28, 2009 7:21 am
by KiwiBacon
Spring washers make it harder for the nut or bolt to escape once it's loose. The manual is correct that they don't make any difference when the bolts are tight.
Posted: Sat Feb 28, 2009 7:21 am
by GUte
G'day Dooley, they're not a lock. They help the nut from shacking loose. your bset bet its to go to a bolt supplier and have a look at the range of washers and nuts avail. as there is many.
Al.
Posted: Sat Feb 28, 2009 8:29 am
by Skegbudley
Yep, thats why we have loctite.
Posted: Sat Feb 28, 2009 9:05 am
by Yom
im more a fan of flat washer and then 2 nuts.
not annoying like loctite and doesnt wear out like a nylock nut.
Posted: Sat Feb 28, 2009 9:09 am
by KiwiBacon
I'm a fan of keeping nuts tight so they don't rattle loose.
Nothing like a bit of rust to keep them together forever too.
Posted: Sat Feb 28, 2009 9:16 am
by Yom
KiwiBacon wrote:I'm a fan of keeping nuts tight so they don't rattle loose.
Nothing like a bit of rust to keep them together forever too.
apparently nissan used this theory on the GQ bodymounts.
I'm about to find out!
Posted: Sat Feb 28, 2009 9:16 am
by Skegbudley
KiwiBacon wrote:I'm a fan of keeping nuts tight so they don't rattle loose.
Nothing like a bit of rust to keep them together forever too.
You live in NZ so you have to keep your nuts tight cause its cold.
I live in Queensland, Australia where its hot so I keep my nuts loose. I just don't want them to fall off.
Posted: Sat Feb 28, 2009 6:59 pm
by Zeyphly
Norlock washers are awesome for holding things tight.
Posted: Sat Feb 28, 2009 7:27 pm
by Yarno
Loctite everyday of the week, just need to use the right one....
Posted: Sat Feb 28, 2009 7:28 pm
by RED60
Read "Engineer to Win" it gives you the rundown on bolts n nuts etc..
Posted: Mon Mar 02, 2009 11:25 am
by bazzle
Yom wrote:KiwiBacon wrote:I'm a fan of keeping nuts tight so they don't rattle loose.
Nothing like a bit of rust to keep them together forever too.
apparently nissan used this theory on the GQ bodymounts.
I'm about to find out!
Locktite on 2 rears, use heat down the top inspection hole.
Bazzle
Posted: Mon Mar 02, 2009 9:22 pm
by Rilux
Spring washers are used so the nut or bolt push up against the thread, thus locking it. I saw that description by the NASA manual, and it's wrong. A spring washer is at it's most effective when fully compressed, as all springs are.
Posted: Mon Mar 02, 2009 10:07 pm
by Dirty
Spring washers are cheaper than a proper locking nut.
Do you want to do the job well, or cheap.
Pick one.
- David.
Posted: Tue Mar 03, 2009 8:17 am
by Wooders
Locktite & Torque wrench.
Posted: Tue Mar 03, 2009 9:12 am
by Dooley
Rilux wrote:Spring washers are used so the nut or bolt push up against the thread, thus locking it. I saw that description by the NASA manual, and it's wrong. A spring washer is at it's most effective when fully compressed, as all springs are.
That's the theory... but from what I've been reading, by the time the washer starts acting like a spring again, the bolts that loose that you're stuffed.
http://www.eng-tips.com/faqs.cfm?fid=1257 wrote:When a lock washer is fully compressed, as it is in a joint that is holding its design preload, the lock washer behaves exactly like a flat washer with a crack in it. Or, if you prefer, a spring that has gone solid. It no longer acts like a spring in further compression and its stiffness, as it relates to the joint performance is determined by the modulus of elasticity of the material.
If the joint loosens sufficiently so that the lock washer acts like a spring again then the joint has lost its design preload and the only tension left in the bolt is whatever small amount that is provided by the lock washer. It doesn't matter. The joint has already failed. The lock washer may postpone the inevitable departure of the nut from the end of the bolt.
http://gltrs.grc.nasa.gov/reports/1990/RP-1228.pdf wrote:The lockwasher serves as a spring while the bolt is being tightened. However, the washer is normally flat by the time the bolt is fully torqued. At this time it is equivalent to a solid flat washer, and it's locking ability is nonexistant. In summary, a lock washer of this type is useless for locking.
At the moment I've just been using loctite or nyloc....
Posted: Tue Mar 03, 2009 6:03 pm
by Shadow
a spring washer only really stops you losing the nut after the nut comes loose, as your descriptions so poetically describe.
loctite is the answer.
Posted: Tue Mar 03, 2009 8:21 pm
by bru21
Use cone nuts for critical applications - no manufacturer uses anything else on critical components. At obc I had 4 nylocs come very loose - they are false hope at best. I bought a box of cone nuts in each size and haven't looked back.
Posted: Tue Mar 03, 2009 8:42 pm
by Shadow
bru21 wrote:Use cone nuts for critical applications - no manufacturer uses anything else on critical components. At obc I had 4 nylocs come very loose - they are false hope at best. I bought a box of cone nuts in each size and haven't looked back.
cone nut, is that like toyota hubs etc, with the cone washer and a nut ontop (or integrated the cone washer into the nut, same same)
?
Posted: Tue Mar 03, 2009 9:40 pm
by Wooders
Nope I am pretty sure he's referring to a CrushLock - where the top of the nut has been slightly pressed in to provide the locking action. These are FAR superior to the Nylocks.
Posted: Tue Mar 03, 2009 9:45 pm
by macca81
Wooders wrote:Nope I am pretty sure he's referring to a CrushLock - where the top of the nut has been slightly pressed in to provide the locking action. These are FAR superior to the Nylocks.
i agree they are, but it looks like they fark the thread on the bolt... iv never had the need to take one off yet and reuse it so i could be wrong, but by appearance it seems that its a one off use type thing...
Posted: Tue Mar 03, 2009 10:52 pm
by Dirty
Each have their place.
Nylocks do not like any type of heat, but can be re-used in a pinch.
Crushlocks are a one use deal, but grip the thread well (possibly too well depending on the materials in question)
- David.