Genmitsu CNC Router 3018- PROVer Mach3 Bedienungsanleitung Seite 19

Step 2: Loosen the Spindle Mount Hex Screw
Step 3: Slide the spindle into the mount until the external sleeve of the spindle is fully inserted
Step 4: Tighten the Hex screw to secure the Spindle. Do not over tighten the screw, as it can damage the mount.