ISC Rigging Block for 5/8 in Rope (Blue/Orange)

The ISC rigging block for 5/8 inch rope is a mid-size block for the everyday removal work most crews do, with a blue frame and orange wheel that are easy to spot in the gear bag. It gives your lowering line a smooth redirect that saves rope and protects the tree.

Where it fits in a rigging system

A rigging pulley replaces a natural crotch as the redirect for your lowering line. Hang it from a rated sling on a sound anchor above the work, run the rope through the sheave, and take it down to a lowering device at the base. The ground worker gets steady, predictable friction from the device instead of uneven crotch friction.

Size it to the rope and the load. The pulley and anchor see roughly twice the rope tension because the line pulls from both sides, and pieces that fall before the catch add shock load. Keep drops short and let the rope run slightly to soften the stop. Check ISC's published ratings before sizing it to a job.

For most crews, 5/8 inch is the everyday rigging size, so this block sees steady use on removals of all kinds. It rides on the saddle without much bother and can be set as you climb.

Inspection and care

Spin the sheave by hand and make sure it runs smoothly with no wobble. Look for cracks, bent side plates, wear grooves, and loose fasteners. Retire a pulley that has been dropped from height onto a hard surface or overloaded. Compare models in our rigging blocks section.

Rigging forces are dynamic and can be several times the weight of the piece. Follow the manufacturer's ratings and ANSI Z133, inspect every component before the job, and keep rigging work to trained crews.