Belleville Spring

I was flicking through my new copy of “Standard Handbook of Engineering Calculations”, and saw something that looked surprisingly familar, but somewhat out-of-context.

What looked just like an arbor washer (used on a tablesaw in between the arbor nut and the blade), was a Belleville Spring, and it is the sort of application that a Belleville Spring is used for – preloading bolted assemblies, and in the case of a tablesaw, it is used to transfer the tension in the bolt to the side of the blade so it doesn’t slip under load.

The original arbor washer on my tablesaw was either underrated (or I was too aggressive in tightening) because it collapsed early on, and I have since replaced it with a rigid arbor washer.

Interestingly, Belleville springs (also known as coned disk springs, or cupped spring washers) are stackable, and can be used in parallel (producing a stiffer spring with the same deflection), or opposite resulting in a lower spring constant with greater deflection.  The ability to finetune stacks of Belleville springs is a big reason why they are used on Formula 1 cars.

Belleville Stack

There is probably no benefit in knowing this from a woodworking application, but I do like understanding why things are designed as they are.

%d bloggers like this: