Securing rigging screws?

[Clyde_Wanderer]

Noticed one of my Cap shroud rigging screws came loose on sat, they dont have any locking nuts on the and they are 7/16 open type.
What is the best way to lock them off?
TIA, C_W

[Pete Cooper]

On Capricious I found that 3mm bolts just fit through. I couldn't find nyloc nuts in that size, so I fitted a stainless steel spring washer under the plain nut. The bolt is long enough to prevent relative movement between the body and the threaded portions, bit not long enough to need taping over.

[Clyde_Wanderer]

Thanks Pete that sounds like a good setup.
Thanks.
Eamonn.