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Old 04-26-2011
DrB DrB is offline
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Thru-Hull Thread count

A standard mushroom 3/4" thru-hull has 2 inches of threads. Based on the thickness of my hull and base mounting plate for the seacock, I estimate count that the I can get 6 full turns before the thru-hull is flush with the hull and therefore can not be turned anymore. I would need to purchase the Long version if I wanted more. The seacock flange will allow 12 full turns before it bottoms out.

Here is the $64,000 question, do I need more threaded turns or is 6 adequate? If 6 is okay, what is to few? I was told in my youth that if you can at least 4 full turns, you have reached essentially the strength of the thread and more turns doesn't buy significantly more strength. T or F? There is adhesive on the threads too.

Any machinists, Mech E or generally smart people care to weigh in?


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