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-   -   Belleville washers: wet or dry? (https://vansairforce.net/community/showthread.php?t=177710)

Navy76 12-12-2019 11:23 PM

Belleville washers: wet or dry?
 
I watched Vic Syracuse?s excellent webinar on RV maintenance this evening and learned a lot! Thanks, Vic!

I would like to see what others think about Belleville washer installation. On page 40A-07 the note on Step 2 says:

?NOTE: Belleville washers are slightly cupped and in order to function properly the outside perimeter of both washers must be in contact with each other when installed. See Figure 2. Install the washers dry.?

In his presentation, Vic recommends greasing the washers to prevent corrosion and other threads in this forum favor grease as well. I have tremendous respect for Van?s and Vic and, as a first time builder, would normally not question advice from either but it seems as though they can?t both be right.

So here?s the question to my fellow builders... Which is correct in this case, and why?

Mich48041 12-13-2019 04:07 AM

According to the following two websites, Belleville washers should be lubricated.
https://www.machinedesign.com/techno...es-put-squeeze
http://www.bellevillesprings.com/dis...nstalling.html
However, Van's might know something about their application that the washer manufactures do not.

Larry DeCamp 12-13-2019 05:30 AM

Here is a tiebreaker for you !
 
Call Craig Catto. He sells the washers and has skin in the game. I anxiously await your finding because I have two setts of washers on order.

JDA_BTR 12-13-2019 06:03 AM

The plans don't say to lubricate them. I inadvertently greased them very well when I greased the nose tube. When they were greased I couldn't get the nose wheel breakaway force to stay set. I cleaned off all the grease, reassembled, tightened, and have had great wheel performance for 80 hours.

Mine are thus lightly lubricated as I didn't super clean them, just gave them a good drying with a blue towel. But I won't be greasing them again.

rv7boy 12-13-2019 06:26 AM

Orientation
 
Belleville washers are really springs. Be sure to install them as specified by the designer. I’m not familiar with how many are used on the RV-10 landing gear, but I know first hand what can happen when Belleville washers are stacked as “washers.”

The orientation of multiple Belleville “washers” can have a drastic effect on the spring constant of the stack.

Clarification: For multiple Belleville “washers,” orientation refers to the arrangement of the cup sided face to the adjacent “washer.” They can be face-to-face, back-to-back,or face-to-back with the addition of each “washer.” Yes, it does make a difference. Don’t treat them as just “washers.”

If there ever were a misnomer, this is one. We traced a problem of 55-inch carbon electrodes in a phosphorus furnace slipping in their holders due to Tennessee good ole boys stacking assemblies of 12 Belleville washers any old way.

vic syracuse 12-13-2019 03:08 PM

Hmmm. Perhaps Scott wants to weigh in here, but I've always greased them and have had no problem setting the breakout force. They don't stick, and they don't rust this way.
I've had people call me with steering problems and I have told them how to clean them and put it all back together with grease, and they have called back and told me how much the steering improved.

Vic

BH1166 12-13-2019 03:42 PM

In lieu of safety wire
 
I have used on brake caliper bolts vs safety wire without issue, greaseless. Grease is about environment, not about purpose...right?

AlexPeterson 12-13-2019 03:44 PM

They will get lubricated even if you install them dry, since grease/oil will creep from the bronze bushing onto them.

I would not install them dry.

While we're on the topic of these washers, it's also a good idea to increase the bearing surfaces somewhat (they are basically a sharp edge) as shown here, by using some emery on a flat surface or equivalent. I've not had to adjust mine in 18 years/1700 hours. The sharp edges, if not removed, can carve into the bronze bushing, which will reduce the breakaway torque.


az_gila 12-13-2019 04:23 PM

The Grumman Tiger/Cheetah OH manual calls out the their Bellville washers to be lubricated every annual.

Essentially it's the same design as Vans... :)

rzbill 12-13-2019 05:49 PM

Quote:

Originally Posted by AlexPeterson (Post 1392796)
They will get lubricated even if you install them dry, since grease/oil will creep from the bronze bushing onto them.

I would not install them dry.

While we're on the topic of these washers, it's also a good idea to increase the bearing surfaces somewhat (they are basically a sharp edge) as shown here, by using some emery on a flat surface or equivalent. I've not had to adjust mine in 18 years/1700 hours. The sharp edges, if not removed, can carve into the bronze bushing, which will reduce the breakaway torque.


This is right on. I posted about this issue some years ago but I imagine the pictures are gone with the demise of my photo host. It's not the only issue. The weldment that is the fork travel stop was not made well in my kit. The central tube was proud of the stop plate which made a very small bearing surface area for a quite high load. I have since changed things to provide steel for the belevilles to bear upon.

I lube my washers because they will get greasy on their own. Lubing at install keeps breakout constant. Did it dry at construction but that was 850 hrs ago. Lots learned since then.


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