Smithy fixtures (6)
I believe the answer is:
anvils
'smithy fixtures' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for anvils that I've seen before include "Heavy blocks for the blacksmith" , "Iron blocks for blacksmiths" , "Heavy blocks for blacksmiths" , "Blocks for a blacksmith to work on" , "Iron blocks for hammering hot metal" .)