Step separating nurse from typist's bar (6)
I believe the answer is:
spacer
'typist's bar' is the definition.
The definition suggests a singular noun which matches the answer.
'step separating nurse' is the wordplay.
'step' becomes 'pace' (pace is a kind of step).
'separating' means one lot of letters goes inside another.
'nurse' becomes 'sr' (I can't explain this - if you can you should believe this answer much more).
'pace' inserted into 'sr' is 'SPACER'.
'from' is the link.
Can you help me to learn more?
(Other definitions for spacer that I've seen before include "Eg, a washer" , "one creates gap" , "Thick washer" , "One may prevent physical contact" , "Something keeping apart" .)