Part of joint with number attached (5)
I believe the answer is:
tenon
'part of joint' is the definition.
(type of wooden joint)
'with number attached' is the wordplay.
'with' is a charade indicator (letters next to each other).
'number' becomes 'ten' (ten is a kind of number).
'attached' becomes 'on' (I've seen this in other clues).
'ten' next to 'on' is 'TENON'.
(Other definitions for tenon that I've seen before include "Type of small saw" , "Kind of saw" , "bit of wood?" , "Mortise filler" , "Mortise counterpart" .)