Sandvik 550 052 35 Arm

Positioning equipment where the work requires it is the arm's function, carrying both the mass it holds and the reaction forces generated in use. The loading is combined rather than simple — bending and torsion together — and in practice the pins and bushings at each joint wear long before the structure does.

Because play accumulates from joint to joint, slack that looks minor at one pivot translates into meaningful positioning error at the working end. Renewing the wear items on schedule keeps that error in check. Checking the reference against the machine's parts manual first avoids ordering an arm built for a different configuration. Stalroc quotes this Sandvik part by number and exports worldwide to drilling contractors, with the associated pins and bushings quoted alongside where useful.