Great Planes heavy-duty screw-lock connectors will allow you to safely secure 4-40 (.093") pushrod wire to your servo arm.
This package includes:
Twelve steel Screw-Locks (drilled for .093" or 4-40 pushrod wire)
Twelve steel retaining washers
Twelve 4-40 x 3/16" socket cap screws for securing pushrod wire into Screw-Lock connector
5/32" allen wrench to tighten screws and drilling hole in servo arm