< Back to Articles
Can you thread plastic and metal NPT fittings together?
To be able to thread plastic and metal fittings together the male fitting has to be plastic and the female fitting has to be metal.
When fittings with a tapered thread such as NPT are tightened the male fitting is compressed and the female fitting is stretched (tensile stress). In general most materials have a higher compressive strength then a tensile strength. This is why the female fitting is the one that will crack when over tightened. Therefore the female fitting must be stronger than the male fitting. Metals are stronger than plastics. The female fitting has to be metal and the male fitting plastic.
Please note that mixing metal and plastics is not highly recommend and should be avoided if possible.
Title: Can you thread plastic and metal NPT fittings together?
Description: Combining metal and plastic fittings.
Last Edited: 5/4/2012
The information contained in this article is for general information purposes only. The information is provided by
United States Plastic Corp. and while we endeavor to keep the information up to date and correct, we make no representations or
warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with
respect to the website or the information, products, services, or related graphics contained on the website for any purpose.
Any reliance you place on such information is therefore strictly at your own risk.
In no event will we be liable for any loss or damage including without limitation, indirect or consequential loss
or damage, or any loss or damage whatsoever arising from loss of materials, time or profits arising out of,
or in connection with, the use of this information.