Are pole line fastener threads chased after galvanizing to provide a proper nut fit?

Chased ThreadsNo, they are not. It is true that galvanizing adds a thickness to the threads of a bolt, which makes it imperative that they be spun in a centrifuge to remove the excess zinc from the threads. This is why it is so important that pole line hardware be galvanized via a galvanizing line specially tailored towards threaded fasteners. Chasing the threads is not only a bad idea, but it is prohibited in section 5.4.1 of the ASTM F2329, which covers the requirements of galvanizing threaded fasteners. If bolt threads are chased, they can remove too much zinc, leaving the threads bare and susceptible to corrosion.  It can also remove steel, which can result in fastener threads being out of tolerance.  For more information, take a look at this write up on galvanized bolts and chased threads.

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