DDK - Die Deutschen Klassiker

hi
I had to tighten up one of my ball joint castellated nuts and I was wondering what purpose the "star" washer serves at the bottom of the assembly. Given the torque involved in doing up the castellated nut, the only purpose I can imagine is that it stops you losing the castellated nut if it comes loose rather than keeping it tight. Is that right?
cheers
Will

I don't think so.
The star washer, in conjunction with its split pin, turns the assembly into a "positive locking device".
http://www.roymech.co.uk/Useful_Tables/ ... cking.html

It's true that, in this case, the high tightening torque means the nut is unlikely to loosen through vibration (assuming it's correctly torqued up). But a positive locking device turns unlikely into impossible. Porsche probably felt this worthwhile in such a safety critical place, having no redundancy (unlike, say, wheel nuts), and which is not inspected very often.

Cheers, Richard.

Thanks richard - belt and braces approach. Got it!