…hammered onto steel entry (6)
I believe the answer is:
tights
'entry' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for tights that I've seen before include "Female leggings" , "Leg garment" , "Hose worn by dancers" , "form of legwear" , "Close-fitting female garment" .)