"Tolerances on Plastic and Pipe" is a sentence fragment. It doesn't tell us at all what you want to know about this subject or what you do not understand about this subject. Please, at least complete the sentence for us.
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"Don't disturb my circles." translation of Archimedes last words
..........may be found by referring to the manufacturer.
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"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856