<< Why doesn't a boolean difference between a bolt and a nut work on a thread form on the nut?

Just rotate one of the object!

When curves' generator are aligned Boolean operations are in the fog! :)
(it's also valuable for Fillets or some commands)
Don't ask me why! :) Michael will give you the mystery's explanation!

One's more for my "Trucs et Astuces" (tips & tricks) sorry in French :) http://moiscript.weebly.com/trucs-astuces.html