### Clue: Fixer for boss establishes company (8)
### Answer: SETSCREW 
 ### Explanation: Definition: Fixer for boss
A charade of SETS ('establishes') plus CREW ('company'). Collins: **Setscrew** A screw that fits into the boss or hub of a wheel, coupling, cam etc. and prevents motion of the part relative to the shaft on which it is mounted.