Hmmm. Way back in the Fred Flintsone days, there used to be a handbook put out by ASME on threaded fasteners and it defined 5 classes of fit. Five bolts (or nuts) could have the same nominal dimensions, but the tolerances differed in a way to alter the degree of interaction. Normal was a Class IIIa or Class IIIb fit, which distorted threads elastically. As I recall, a Class V fit was a "slop" fit; until snugged up, there was a gap between bolt and nut (or threaded hole) threads and Class I fits caused permanent deformation of threads with perhaps some pressure welding.
I wonder if the "C5" refers to a set or class of tolerances, then. The "4.8" would refer to the diameter and thread spacing as normal for metric fasteners. Jim On Wednesday, 2004 January 28 01:05, Pat Naughtin wrote: > Dear All, > > Could someone tell me where I might find an explanation of this letter and > number combination found on the head of a bolt. > > C5 > 4.8 > > Thanks, > > Pat Naughtin LCAMS > Geelong, Australia -- James R. Frysinger Lifetime Certified Advanced Metrication Specialist Senior Member, IEEE http://www.cofc.edu/~frysingj [EMAIL PROTECTED] [EMAIL PROTECTED] Office: Physics Lab Manager, Lecturer Dept. of Physics and Astronomy University/College of Charleston 66 George Street Charleston, SC 29424 843.953.7644 (phone) 843.953.4824 (FAX) Home: 10 Captiva Row Charleston, SC 29407 843.225.0805
