Washer under Bolt or Under Nut?

[Ralf11]

ok, here's one...

A bolt goes thru 2 pieces of sq. tubing to hold them together. This is in a 'kit' to build something and all hardware is supplied by the manf. Only a single washer is supplied for each bolt/nut set. Each end is free to rotate.

Where does the washer go?

And why?

 

[infinkc]

Under the nut, since the nut will be spinning as you tighten. If it were me I would get more washers for both sides.

 

[duneslider]

If they are round holes correctly sized then technically you don't need any washers, assuming material thickness is adequate.

I usually add washers to the nut side when I spec things out. If there are slotted holes, or oversized holes the washers are needed. Sometimes I will used flange bolts/nuts instead of washers. Lots of acceptable options.

 

[MikeF2316]

Under the nut, since the nut will be spinning as you tighten. If it were me I would get more washers for both sides.

This is exactly what I'd do.

You're supposed to hold the bolt still and turn the nut (if possible), so if there's only one washer it goes under the nut.

 

[kbs2244]

as said.
witch ever end is being turned
the idea is to protect the surface from stress making scratchs

 

[bbbarracuda]

Do the two tubes rotate against each other? The washer go between them?

 

[Copymutt]

The thinner the wall of the tube the more need for a washer.

 

[Dan in Pasadena]

Under the nut, since the nut will be spinning as you tighten. If it were me I would get more washers for both sides.

This^^

 

[dogdog]

If they are round holes correctly sized then technically you don't need any washers, assuming material thickness is adequate.

I usually add washers to the nut side when I spec things out. If there are slotted holes, or oversized holes the washers are needed. Sometimes I will used flange bolts/nuts instead of washers. Lots of acceptable options.

^^^^
I would agree with this.

It would be dependent on the application of your nuts/bolts... is it a flat washer ? locking washer , torque limiting etc?

 

[Ray-CA]

Print this and place it on the wall of your shop......

 

[Ralf11]

Under the nut, since the nut will be spinning as you tighten. If it were me I would get more washers for both sides.

"Each end is free to rotate." and will do so when tightening

 

[Ralf11]

^^^^
I would agree with this.

It would be dependent on the application of your nuts/bolts... is it a flat washer ? locking washer , torque limiting etc?

sorry they are all flat washers

my bad for not stating that

 

[toolchaser]

I was taught if you only have one, put under the nut, for the above reason.

 

[AP514]

+1 for under the NUT

 

[sz0k30]

100% under the nut.

 

[rlitman]

I was taught if you only have one, put under the nut, for the above reason.

I have a drawer of washers to fix just this issue.

 

[Ilikeike]

"Each end is free to rotate." and will do so when tightening

Got to be difficult to tighten if the other side is spinning.
That or you will have a tool to hold the other side, so hold it and keep it from spinning and put the washer under the nut.

 

[bwringer]

I have a drawer of washers to fix just this issue.

Lookit Mr. Moneybags over here with all your fancy-schmancy extra washers just hanging around...



Seriously, if it bugs you, go spend the ha'penny each for more washers. Otherwise just put the washer on the nut end and think about something more interesting.

 

[rlitman]

Lookit Mr. Moneybags over here with all your fancy-schmancy extra washers just hanging around...



Seriously, if it bugs you, go spend the ha'penny each for more washers. Otherwise just put the washer on the nut end and think about something more interesting.

LOL, pretty much. Years ago, I bought a nice wooden cabinet system with drawers filled with all sorts of hardware. It had washers beautifully organized until I dropped that drawer. Now, I just pick through the mess (the stainless and brass stuff is still organized, and what I've bought in boxes since is as well).

More often than not, if I'm buying hardware for a project, I'll buy a box of washers rather than the dozen or so I need. It costs a little more, but I always end up happy that I've got extra washers sitting around later on.

 

[ducksface]

Other than a wallered out hole or an oversized hole or as added material against a tear out, or as a spacer why a flat washer at all?
If marring the finish under the nut is a thing(on a common job), I don't what the pressure ring from the washer would be.

This should be the 'more interesting' as requested above.
Washers aint needed just cause you gots washers.
I say flat washer use is over blown just like 3month/3,000 oil changes. Hyperbole.

 

[niget2002]

Scratches invite rust. A nut or washer rusting is easy to replace. A metal part rusting because the nut scratched it up while tightening is more difficult/expensive.

Sent from my LM-G820 using Tapatalk

 

[Milton Shaw]

Make sure it is a lock nut (nylock or similar). If the tubing flattens any the nut will be loosen and come off. Tubing will bend/flatten if tighten too much or much pressure is put on it. The washer generally goes under the nut as everyone else has said. Think of all the mower handles tubing you have seen that are loose, they almost always use locking nuts for that reason.

 

[MAYOR28]

I have a little experience in this area, aircraft engineer by day .....or at least one that designs component shelfs for a living.....

We ALWAYS use 2 washers, one under the head, one under the nut. The washer serves a couple purposes, 1. it stops the parent metal (the actual structural components) from wearing when tightening the fastener, 2. distributes the load slightly past the stress riser caused by the hole in the metal, and 3. serves as somewhat of a barrier for the always present dissimilar metals (galvanic corrosion is always a problem to avoid).


All that being said, if you only have one washer, you put it under the side that is being driven, most typically that is the nut side. Unless you have nutplates (aircraft stuff).


Also, did you know there is a MIL-SPEC defining the difference between screws and bolts?

...

 

[rattle_snake]

fastener science is quite interesting. To me anyhow.

It can be argued that a plain 'washer' lowers frictions (as it acts like a thrust bearing) and can allow a fastener to come loose easier.

But I'm a washer ***** at times and buy them by the box of 100. My engineer OCD mandates SAE washers cuz the USS type are to loose...