A mechanical base (6)
I believe the answer is:
bottom
I believe this clue is a double definition.
'a mechanical' is the first definition.
(a 'mechanical' from A Midsummer Night's Dream)
'base' is the second definition.
(I've seen this before)
(Other definitions for bottom that I've seen before include "Shakespearean weaver" , "far end" , "Lowest position" , "Lowest part or underside" , "Last" .)