So tried to remove a lock from a chest, was wearing toolbelt, nothing
in held or wielded.
You start concentrating on the skill.
You are prepared to do the skill.
A blue flicker surrounds your hands.
You need a real hammer to proceed.
Would be nice if merchant toolbelt hammer worked for detaching locks
as well as attaching.
It should work, and did just as I tested it myself. The "You need a real
hammer to proceed." is a somewhat misleading message, but the blue flicker
basically means that belt item would be used, but there are no free wield
limbs.
I realize you stated that you were not wielding anything, but I cannot check
this post-de-facto.