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.
Perhaps you can see a link between them that I don't see?
'this man' is the wordplay.
I cannot quite understand how this works, but
'man' could be 'der' and 'der' is found in the answer.
This explanation may well be incorrect...
'is a' acts as a 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" .)