any benefit to using a washer?

[snowman3]

I asked a few friends and some workers at the big box stores and got different answers, so figured I'd come here and ask the experts.

I mounted some indoor shelving using L brackets and a board on top. The brackets aren't flimsy, probably 3/32" thick and has a cross-brace. (Bracket is triangle shape, not L shape).

I used lag screws 1/4" diameter and 2" long to get through drywall and into the 2x4 studs.

Out of habit I put a washer under the head of the screw to distribute the force. But then I noticed the hole in the bracket was same size as hole in the washer. The bracket is 2-3x thicker than the washer, not much risk of the hex head pulling through.

If you are mounting a smooth steel plate to wood like that, does the washer provide any benefit?

 

[Bondo]

I asked a few friends and some workers at the big box stores and got different answers, so figured I'd come here and ask the experts.

I mounted some indoor shelving using L brackets and a board on top. The brackets aren't flimsy, probably 3/32" thick and has a cross-brace. (Bracket is triangle shape, not L shape).

I used lag screws 1/4" diameter and 2" long to get through drywall and into the 2x4 studs.

Out of habit I put a washer under the head of the screw to distribute the force. But then I noticed the hole in the bracket was same size as hole in the washer. The bracket is 2-3x thicker than the washer, not much risk of the hex head pulling through.

If you are mounting a smooth steel plate to wood like that, does the washer provide any benefit?

Nope,... Not at all,....

 

[rburke65]

Washers are used to distribute a load so in your case I don't think the washer would serve a purpose. IMO......

 

[nehog]

They do serve a purpose--they make me feel better when I use them! (I was taught that a washer reduced friction of the head against the item... As if that is a big problem, right?)

 

[brownbagg]

washers are like footers on a foundation, it spread the load out on the surface

 

[BD1]

^^^when you tighten the head will dig into washer and not into the finished surface.

 

[dfiler2]

I don't think there would be any benefit in this situation, I'm guessing other parts of the system would fail first. I was hoping this thread was on a different subject and help me make a decision, I am still beating my clothes on a rock down by the river to wash them.

 

[MFolks]

"Fender Washers" might work, as they have larger diameters, than SAE, or USS washers.

 

[toplessHO]

I put washers everywhere I can.Not only does it help with all mentioned above but looks better too

 

[srmofo]

I put washers everywhere I can.Not only does it help with all mentioned above but looks better too

Same here

 

[Cyberbear]

I suppose a mechanical engineer would have all the technical answers to what a flat washer is good for besides the obvious reasons others have posted.
Basically, as I see it, using a flat washer never hurts and often helps. Putting a thinner washer on top of heavier material is often pointless, unless you don't want the socket scarring up the item being installed. In other words, washers are cheap and it can't hurt in most applications, and it lends a complete or finished appearance.

 

[LS6 Tommy]

It never hurts for general applications, but ther are some fasteners where they are not supposed to be used, like flywheel bolts, cylinder head bolts, "shouldered" bolts or when the underside of the fastener head has a serrated seat.

Tommy

 

[volleyball]

It does depend on the application. For the one mentioned, it doesn't seem to help.

 

[404]

No washer with a hex head looks like a hack. Scratches all around the head. Flanged hex head okay with no washer.

 

[PCO6]

When it comes to washers I'm always reminded of Colin Chapman's words on the subject ... "We wouldn’t put a washer underneath the head of a bolt, why…wh..what are you going to do that for? Why do you want to take the washer around the track?”

 

[QwikKotaTx]

As some have alluded to, washers are used when the bearing force of the material exceeds the load placed upon it by the nut or bolt. The washer is used to increase the area this load is applied to, thereby reducing the stress. I too prefer flanged nuts/bolts and when working cars they are 10x easier to manage.

 

[saceone]

washer crew checking in !

 

[MotoDave]

A GOOD washer will also be harder than what you're bolting through, so it'll help distribute the force and prevent the bolt head from digging into the material.

I believe in using washers under the part that's being turned, but it doesn't hurt anything to use on both ends. In your case you're not using a nut so I would use a washer for sure.

Not split lock washers ... that's a whole other argument

 

[Indyducati]

Please correct me if I'm wrong, but there is a right and wrong side of a washer.

Most, common, flat washers are stamped out. One side of the washer will have
a 'edge'. The other sides edge will be smooth. That smooth side should make contact
with the 'material'. Stress riser avoided.

It's probably not important in most applications, but you never know
when you'll be working on a jet engine or mechanical heart

Steve

 

[MackMan]

Please correct me if I'm wrong, but there is a right and wrong side of a washer.

Most, common, flat washers are stamped out. One side of the washer will have
a 'edge'. The other sides edge will be smooth. That smooth side should make contact
with the 'material'. Stress riser avoided.

It's probably not important in most applications, but you never know
when you'll be working on a jet engine or mechanical heart

Steve

You have a valid point here, though I always did this the other way around. I put the smooth side against the turning portion (bolt head) to reduce friction. When you torque a fastener a huge percentage of the effort you put into it is overcoming under-head friction, so reducing this friction improves your efficiency. Also, it looks a little nicer I think.

And yes it does make a difference, I spent a few years being the "go to" guy for fastener testing at my company, and always using the same side of the washer gave much more consistent results than not (i.e. the coefficient of friction is different on each side)

Sometimes with the rough side against the bolt head the washer will spin with the bolt instead of the bolt spinning on the washer. This created havoc on surfaces that were painted or otherwise had an applied surface treatment as the spinning washer would start to gouge the surface treatment which also throws required torque value all over the place since now your coefficient of friction is changing as you apply load. Also it looks bad, and presumedly opens you up to corrosion issues.

I am a fan of washers.

 

[Indyducati]

MackMan, you too have a valid point ! My opinion is lore, passed from my Journeyman to me, the apprentice, years ago.

We've each got a 50% chance of being correct !

Steve

 

[laser3kw]

Not split lock washers ... that's a whole other argument

Ya - that is an on going argument where I work. I agree that we use them in too many spots, management says to eliminate them all together.

 

[MackMan]

Ya - that is an on going argument where I work. I agree that we use them in too many spots, management says to eliminate them all together.

I agree with management. Useless. In all my testing these just complicated things. In durability/vibration testing they've shown to have basically no effect.

 

[volleyball]

I am with mackman for the side of washer, it also looks better. If the washer spins with the bolt, you lose some of the benefit.
What I don't get is washers that are hardly any bigger than the screw/bolt head.

 

[dawgee]

split lock washers are useless. most people think they are suppose to "bite" in where the split is not so they are suppose to work on "spring" pressure they would have to be so thick for it to work like that it would be nuts

 

[MackMan]

I am with mackman for the side of washer, it also looks better. If the washer spins with the bolt, you lose some of the benefit.
What I don't get is washers that are hardly any bigger than the screw/bolt head.

I don't like those either but there's still at least 2 benefits.

1) Overall area will still be larger than hex bolt head

2) Still spinning bolt/nut on washer avoids gouging/scarring the structural material.

 

[MackMan]

split lock washers are useless. most people think they are suppose to "bite" in where the split is not so they are suppose to work on "spring" pressure they would have to be so thick for it to work like that it would be nuts

Quite true. The quest for a fastener that maintains clamp load in high vibration has a lot of expensive research behind it, and still no 100% effective solution. Chemical lock patches, "crimp" nuts and some exotic threads (huck-spin) seem to be the best.

For most of what I do personally I'm a fan of "nylock" type nuts, but that's basically for applications where I just don't want the nut to fall off if it did start to loosen. When you're trying to hold 80,000lb+ of truck together there's better solutions.