Small thread advice - anti loosening
Hi
First off I have searched. The searching has made me fully realise (vs only suspecting) that this subject is not simple but that I want to learn, to understand. Thanks.
I have a small circular shaft (8mm dia) that I need to attach to another circular shaft (12mm dia).
Once connected the 8mm dia shaft will very often be rotated back and forth by a handle (max 100mm long) at its end which can be up to 150mm.
Quite obviously, the 'leverage' (apologies but don't know the correct terms) from a handle 100mm long on a shaft 150mm long is much more than on a shaft 30mm long. As the handle is used to open and close something on the end of the 12mm shaft human beings will try to 'make sure' it fully opens and closes. This would put great stress on the join of the two shafts eventually, at least in my mind, causing the joint to loosen or fail.
My current idea is to thread (5mm so it has a shoulder and sits square against the 12mm shaft) the joint and apply a lock nut and then put in a grub screw at 90 degrees to the thread through the 12mm shaft to completely lock the joint so it never works loose.
However, my instinct is that it will eventually fail. Does anyone have any advice please?