Stable part of wooden frame (4)
I believe the answer is:
stud
'stable' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for stud that I've seen before include "Specified arrangement" , "Item designed to grip" , "equine establishment" , "Macho man" , "Breeding stable" .)