Cutter one has boarded didn't appear to reverse (5,3)
I believe the answer is:
tenon saw
'cutter' is the definition.
(something which cuts)
'one has boarded didn't appear to reverse' is the wordplay.
'has boarded' indicates putting letters inside (inserted letters come on board).
'didn't appear' becomes 'wasn't' (roughly synonymous).
'to reverse' shows that the letters should be reversed in order.
'one' placed into 'wasnt' is 'wasnonet'.
'wasnonet' back-to-front is 'TENON-SAW'.
(Other definitions for tenon saw that I've seen before include "One cuts" , "Tool used for making wooden joints - wants one (anag)" , "Woodcutter" , "used in joint production" , "Precision cutter for making wooden joints" .)