Select digger (4)
I believe the answer is:
pick
This clue might be a double definition.
'select' is the first definition.
(picking is a kind of selecting)
'digger' is the second definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe you can see an association between them that I don't see?
Can you help me to learn more?
(Other definitions for pick that I've seen before include "tool - it breaks" , "Select - implement" , "Pluck" , "tool for breaking rocks" , "Choose, select" .)