Perfetto Knob Removal Guide for ARO® Grinder Setting Dial
The ARO® Grinder Setting Dial for Eureka Mignon is fully compatible with the Perfetto. However, the factory Perfetto knob is a multi-piece, set-screw-secured assembly and does not simply unscrew like other Mignon models. Follow the steps below to remove it safely.
Tools Required
- 2.5 mm hex key (Allen key)
Important Note
The Perfetto knob uses a brass inner hub secured to the grinder shaft with a set screw. This screw must be loosened before the knob will unscrew. Forcing the knob without loosening the set screw can damage the grinder shaft.
If at any point during this process a component requires excessive force to loosen or unscrew, stop immediately and contact us for assistance. Forcing any part of the grinder can result in severe and irreversible damage.
Step 1: Remove the Top Cap
Remove the top cosmetic cap from the knob to access the internal brass hub and set screw. Simply lift it off as it is a light snap-fit.

Step 2: Loosen the Set Screw
Insert a 2.5 mm hex key into the set screw and turn counterclockwise. Loosen only until the hub is no longer clamped. There is no need to remove the screw completely.

Step 3: Unscrew and Remove the Knob
Turn the knob counterclockwise to unscrew it from the grinder. Apply steady pressure only. Do not use pliers or tools.
Step 4: Install Your ARO® Geared Knob
With the factory knob removed, install your ARO® Grinder Setting Dial and Geared Knob using the standard ARO installation method found here.