I don’t know of any aftermarket replacement for the original ones with flat lug nuts, used at least through 53 but I haven’t looked in parts book to know full year range.

Dexter trailer axles may offer clamp plates for 5/8 studs. We just got a trailer and wheel torque specs in the manual are different for different nut types and clamp plates are shown as an option, not what we have though.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-