Do you have a micrometer?
How confident are you with taking accurate measurements with a dial caliper? If you have a good sense of feel you should be able to decide if it is worn too much or not with the calipers.

Grigg


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-