Ordered a plane spherical bearing used on hydraulic cylinders for compensating for misalignment. 2 1/2" I'd, 4 3/8" od, about 7 pounds. Overkill but the eBay price was right. 14 deg of angle one way should give about 18" of blade bevel in 75" blade width. 4" sch 40 pipe split with clamping bolts should make a socket for the bearing. To be continued.....