Belleville Washer Stacks

Palmer Reising


Do you see any problem with using an eight (8) Belleville washer stack on the 1/2 inch Propeller bolts on a Cozy III with an O-360 or would you suggest buying new bolts and using a four or six stack? Catto Propellers didn't seem to have any objections since they sent 24 additional Belleville washers.

Also, should I use a wide area washer against the crush plate with the stack. One wasn't there in the original installation (see photograph).

What would the proper configuration of all washers (thin, Belleville, medium and wide area) in each stack of eight be?


I'm installing a new Catto Three-Bladed Propeller and the hub is around 92 millimeters thick. The original Three-Bladed Catto propeller's hub is around 116 millimeters thick. The previous Propeller is significantly heavier....maybe, 10+ pounds. I haven't weighed them yet.

The propeller bolts bottom out with around 22 threads protruding. There are about 32 threads on the bolts. With the previous propeller, there were, about, eight threads protruding. The new propeller hub is around 92 millimeters thick. The previous Propeller hub is about 116 millimeters thick. Two Belleville washers are about six millimeters thick. If I add four Belleville washers per bolt, bringing the total to eight per bolt, I'll have around 17 threads protruding. That leaves around five threads before bottoming out.

However, if I also use the wide area washer against the crush plate as shown in the PDF document about how to keep a wooden propeller on an aircraft with less work, I could gain about two threads more before bottoming out. Thus, I would have around seven threads before bottoming out.


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