Slot.it SIGMF60 lock-ring ferrule for M-series modular inline crown gears using 6.0 mm pinions.

The modular Slot.it crown system separates the centering/locking hardware from the crown itself. SIGMF60 is the ferrule that lets the same modular crown work with a 6.0 mm pinion, while the free-running steel washers reduce rubbing between the motor shaft and crown assembly.

Why use the 6 mm ferrule?

• More setup flexibility: it lets an M-series crown be matched to a 6.0 mm pinion without replacing the crown.
• Reduced friction: the modular washer arrangement minimizes direct sliding contact in the drivetrain.
• Precise axle location: the lock ring fixes the assembly securely on a standard 3/32" axle.
• Race-serviceable design: changing between the 5.5 and 6 mm systems only requires the correct ferrule rather than a completely different crown system.

Pro assembly notes

Use the correct calibrated washers, apply only a light film of oil, and verify that the grub screw goes through the crown hub opening and actually bears on the axle. A free-spinning drivetrain with minimal side play is the goal—tight is not the same thing as properly adjusted.

Jim's setup note: The 6 mm ferrule is useful when your chosen pinion/motor combination benefits from the larger pinion diameter. The modular crown lets you make that change without giving up the low-friction crown design.

Specifications

• Manufacturer: Slot.it
• Part number: GMF60 / SIGMF60
• Type: Modular crown lock-ring ferrule
• Pinion diameter: 6.0 mm
• Axle: 3/32" / 2.38 mm
• For: Slot.it GM-series modular inline crown gears
• Scale: 1/32
• Country of origin: China
• HS code: 9503.00