This man is a steel erector (6)
I believe the answer is:
spider
'steel erector' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'this man' is the wordplay.
I cannot really see how this works, but
'man' could be 'der' and 'der' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
'is a' is the link.
Can you help me to learn more?
(Other definitions for spider that I've seen before include "Bathtub intruder - snooker rest" , "A crawler" , "Web expert?" , "Insect-eater" , "A common arachnid" .)