O.S. Engine OS79871420 M4x20 Hexagon Socket Head Cap Screw 10-Pack  [OS79871420]

M4x20 Hex Socket Cap Screw Details

This 10-piece set of M4x20 hexagon socket head cap screws is designed for scale RC tasks such as fastening engine mounts, accessory brackets, and small assemblies on model cars and boats. The M4x20 code denotes a 4 mm thread diameter with a 20 mm length, making selection straightforward when replacing common fasteners.

These screws provide consistent clamping where repeatable spacing and torque are important. Correct thread engagement and avoiding over-torquing help protect tapped holes in engine mounts and nearby structural parts. For components exposed to vibration, confirm proper seating of the M4 thread to maintain retention.

Installation tips include verifying each screw fully engages the mating thread, replacing any screws with head or thread damage, and keeping a small stock of spares for field repairs. The 10 pcs quantity suits small rebuilds and routine service without extra parts clutter.