CAT 342-8909 455mm Long Trunnion

CAT 342-8909 is a Caterpillar welded trunnion (spherical with journal type), adapted to the boom, stick, or connecting rod hinge points of excavators and loaders for bearing radial loads and oscillating conditions. The following is structural engineering information.

Core Parameters (Professional Version)

Project Details
Basic Attributes
Model 342-8909, welded fixed trunnion, 2 pieces per unit (symmetrical), compatible with Cat 320/323/336 excavator boom – stick hinge, 938/950 loader linkage – rocker arm connection, bearing radial load + swing conditions, suitable for medium and heavy load and impact scenarios

Key Dimensions
Ball diameter 100 mm, journal diameter 80 mm, total length 120 mm, weld section length 50 mm, journal length 70 mm, chamfered ends C2×45°, mounting hole diameter 22 mm (for locating pins), spherical surface roughness Ra≤1.6 μm, coaxiality≤0.02 mm

Material and Process
Material is AISI 4140 low alloy structural steel, overall quenching and tempering HB280–320, spherical and journal surfaces hardened. HRC50–55, hard chrome plating thickness 0.05–0.1 mm, straightness ≤0.01 mm/100 mm, flatness ≤0.015 mm
Performance Parameters: Radial load capacity ≈80 kN, swing angle ±15°, operating temperature -30℃ to +120℃, fatigue life ≥5000 hours, impact load coefficient 1.2, compatible sleeve bearing 604-6832, assembly clearance 0.02–0.04 mm
Compatible Models: Cat 320D2/323D2/336D2 excavator boom – stick articulated, 938K/950GC loader linkage – rocker arm connection, compatible sleeve bearing 604-6832, seals 420-5763
Installation and Maintenance Points: Before installation, clean the trunnion spherical surface and journal, remove oil and rust from the welded surfaces, and check the bevel angle. For the 30°–35° angle, the clearance between the journal and the inner bore of the sleeve bearing should be 0.02–0.04 mm, and the coaxiality ≤0.02 mm.

Argon arc welding should be used, with a welding current of 180–220 A and an interpass temperature ≤150℃. Post-weld stress-relief annealing (holding at 600℃ for 1 hour) should be performed to prevent welding deformation and cracks. The spherical runout after welding should be ≤0.03 mm.

Apply Cat 106-9900 grease during assembly, filling the grease cavity to 1/2–2/3 capacity. Check the flexibility and lubrication status every 1000 hours. Replace the bearing immediately if the spherical wear is >0.1 mm or the plating peels off.

Regularly inspect weld joints for cracks using magnetic particle testing. Repair or replace any cracks immediately to prevent equipment damage due to hinge point failure.