Flagpole Truck – HDT-1 Heavy Duty Series For external halyard poles — Threaded Type — Revolving — Single Pulley Cast aluminum construction with a 3-7/8″ outside diameter aluminum pulley on 1/2″ stainless steel axles. This truck is designed to be used on flagpoles that have up to a 5-1/2″ outside top diameter with female fitting installed. The bottom of the spindle has a 1-1/4″ NPT threading and is screwed into the top of the flagpole while the top spindle is designed to accept an ornament with a spindle threading of 1/2″-13NC as standard but can be supplied with other sizes of threading. The ornament is secured to the truck with a 1/4″-20NC stainless steel set screw. The truck body rotates on 26 stainless steel ball bearings on cast races. The recommended maximum halyard diameter is 3/8″.