Quote:
Originally posted by mikiec
An additional question about bolts...
What is the difference between a fine thread and coarse thread?
Mike
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Mike...from an article in Stock Car Racing...
"...Given the same alloys and heat treatments, a bolt with fine threads can be tightened to a torque 9 percent greater than one with coarse threads. So why are not all bolts made as fine threads?
Often the material with the internal thread-cast iron or aluminum, for instance-is not as strong as the bolt. The weaker or softer material needs the wider gripping surface of the coarse-thread bolt.
With fasteners that are tightened and loosened frequently, the wider coarse thread has more wear resistance.
The last reason, for me at least, is that the coarse-thread fastener is quicker to use and easier to start the threads together."