Belleville washers-which way to apply?

[nickel plate]

I'm just finishing up a rear remote installation and it is now time to nut down the stack. On the outboard face of the end cap, which direction does the conical/spring belleville washer go? Cone top towards the outboard face of the end cap or cone top towards the nut? I have four threaded rods installed, four of these washers and four nuts to lock down the stack.
Please don't guess-Wikipedia shows a drawing one way and another fastener site describes the other way. I called two local branches of a company named Fastenet and they don't know-how do you succeed in sales if you lack product knowledge? Thanks.

 

[LD1]

I'm just finishing up a rear remote installation and it is now time to nut down the stack. On the outboard face of the end cap, which direction does the conical/spring belleville washer go? .

Not sure on your particular application, but I always put the cone toward the nut on every other thing that I have worked on.

I called two local branches of a company named Fastenet and they don't know-how do you succeed in sales if you lack product knowledge? Thanks.

Thats an easy one. Lots of BS and a good smile

 

[jonyyuma]

All of them I have ever worked on came with the cone towards the nut. They apply a locking force to the nut. They should not be so tight as to flatten out. We have many of them on our electrical gear.

 

[jonyyuma]

Yes, that is exactly how they work, and finished product on the bottom white insert.

 

[Craig Clayton]

As per jonyuma ( They apply a locking force to the nut. They should not be so tight as to flatten out. We have many of them on our electrical gear. )
That is how in the electrical trade I would tighten them down. In the mechanical trade I know they can be stacked to achieve a predetermined thrust load but that is not the subject at hand.
Craig Clayton

 

[jonyyuma]

As per jonyuma ( They apply a locking force to the nut. They should not be so tight as to flatten out. We have many of them on our electrical gear. )
That is how in the electrical trade I would tighten them down. In the mechanical trade I know they can be stacked to achieve a predetermined thrust load but that is not the subject at hand.
Craig Clayton

Craig, you might have me there. Nut down the stack? ? Why not common split lock washer, or better yet a star lockwasher on the nut. Myself I like the Nylock locking nuts..for static loads..Jy.

 

[Craig Clayton]

I think the stack comment has been misunderstood. We have large mechanical machines that have stacked belleville washers in them to thrust against. They are stacked to give a known value . In this way if the thrust exceedes a known movement a microswitch is touched and the thrust action stops. I can not recall if they are back to back or nested.
The only reason the bolts would have belleville washers on hydraulics stacks is for thermal expansion of the block.
Craig Clayton

 

[Baby Grand]

I have used Belleville washers when thermal expansion of the flange is greater than thermal expansion of the bolt - assume aluminum flanges and a steel bolt. This results in the bolt tightening when the assembly heats up. If it tightens too much there's a risk that the aluminum will yield and when the assembly cools back down, the bolt will be loose and may rotate out due to vibration. The Belleville washer's spring effect (if not flattened when installed as some have noted) allows the thermal growth to occur without causing yielding of the flange material.
-Jim

 

[kjung17]

I agree with the majority here. Cone side to the nut. Pay attention to recommended torque specifications to avoid flattening out. We used to use stacks of washes, back to back not nested, to act as a sort of spring tensioner.

 

[FastPauly]

We used them as Baby Grand states....in high temperature applications. On rotary tube furnaces, the tube flange bolts can break if the washers are not used. There is a tremendous amount of force applied to the fastener from the effects of thermal expansion....to the point where thread damage occurs (stretching) or complete failure (breaking). Although somewhat expensive, the use of them greatly reduced the time involved in removal of the bolts....stretched threads are a PITA to deal with. A torch was often used to remove the damaged bolts....which often resulted in damage to the flange faces.

And yes...the cone goes towards the fastener ends.

 

[J_J]

When stacking washers, do you put every other one upside down? If you use only two, is one of them upside down?

I found the answer. There is more than one way to install these washers.

http://www.solonmfg.com/springs/features.cfm

 

[CurlyDave]

If you have four nuts and four Bellevilles, it really doesn't matter which way they go on. They will provide the same spring force in either direction. I would put the smaller bearing diameter against the harder metal.

Now if you have more than one per stud, you need an assembly drawing to get it right.

As J_J points out they can be stacked in all sorts of different ways in various applications. The original design engineer selected a certain stack for a reason.

 

[nickel plate]

Here is the makeup of the hydraulic stack:
first set of remotes 1-1/8" thick steel
second set of remotes 1-1/8" thick steel
Woods BH90-X outer cap 1" thick aluminum
four M8 threaded studs (one at each corner of the stack)
four M8 Belleville spring washers
four M8 nut torque nuts to 24 N-m (18 ft-lbs)

 

[jonyyuma]

We used them as Baby Grand states....in high temperature applications. On rotary tube furnaces, the tube flange bolts can break if the washers are not used. There is a tremendous amount of force applied to the fastener from the effects of thermal expansion....to the point where thread damage occurs (stretching) or complete failure (breaking). Although somewhat expensive, the use of them greatly reduced the time involved in removal of the bolts....stretched threads are a PITA to deal with. A torch was often used to remove the damaged bolts....which often resulted in damage to the flange faces.

And yes...the cone goes towards the fastener ends.

The thermal expansion is the reason our Hi-voltage gear has them on the buss bars. We have never had a failure of a bell washer as the torque rating is important.I have been installing them since the 80's and maintain them now, which is a simple tor. check. Vibration is not a factor here..Jy.

 

[Mace Canute]

If you have four nuts and four Bellevilles, it really doesn't matter which way they go on. They will provide the same spring force in either direction.

Dave, I don't believe that is correct. That would be the case if the nut was large enough to cover the outside edge of the washer, but I haven't seen that to be the case with any belleville washer I have used. When the washer is upside down, only a small portion of the spring material is in use, that which the nut covers and it then acts like a regular flat washer.

 

[CurlyDave]

You are correct if the nut is smaller than the washer.