This video details the completion of a crank drive adapter coupling, following initial lathe work. Precision machining involved CNC milling to accurately drill and counterbore mounting holes for both the crankshaft and a flexible M12 coupling. The critical step was pressing and TIG welding the spline adapter into the housing. This welding process proved challenging, causing repeated surface cracking attributed to the parent metal's prior heat treatment, which necessitated multiple repair passes. The resulting component offers a substantial improvement in design, simplifying future maintenance access to the engine's front section.
Machining and Assembly of the Crank Drive Adapter Coupling
0:09 Milling Setup: Work began by setting up the adapter on a sacrificial aluminum plate on the mill table to facilitate drilling and tapping without damaging the table surface.
1:53 Crank Attachment Holes: The PCD (Pitch Circle Diameter) function was used to accurately map and drill the four bolt holes required for attaching the adapter to the crankshaft.
6:40 Counterboring: The crankshaft bolt holes were counterbored to ensure the bolt heads sit flush with the adapter face.
9:11 Flexible Coupling Holes: Six additional holes were drilled for the flexible coupling; three were clearance holes, and three were prepped for M12 threading.
24:06 Spline Adapter Installation: The machined spline adapter was pressed into the housing before welding.
25:03 Welding Issues: TIG welding the spline adapter using ER70S6 filler rod resulted in a significant surface crack (26:45), which was diagnosed as stemming from the heat treatment characteristics of the base material.
27:19 Crack Mitigation: The crack reappeared after a second pass but was significantly smaller (27:32). Multiple subsequent passes were performed until the crack was resolved, appearing only surface level.
33:39 Design Improvement: The completed component streamlines engine front-end maintenance, allowing the entire hydraulic pump assembly to be removed simply by decoupling the rubber element.
33:55 Final Steps: The finished adapter components will be zinc plated and painted to prevent corrosion before final assembly onto the motor.