Yours truly gripping wood, one old golf club (6)
I believe the answer is:
mashie
'old golf club' is the definition.
(I've seen this before)
'yours truly gripping wood one' is the wordplay.
'yours truly' becomes 'me' (the person that set this crossword).
'gripping' means one lot of letters goes inside another (inserted letters are gripped).
'wood' becomes 'ash' (wood from an ash tree).
'one' becomes 'I' (Roman numeral).
'ash'+'i'='ashi'
'me' placed around 'ashi' is 'MASHIE'.
(Other definitions for mashie that I've seen before include "He aims (anag) - golfer's five iron, formerly" , "Old golf club" , "One of 9 [CLUBS]" , "Old-fashioned golf club" , "Golf club for lofting" .)