There are many types of threaded pipe plugs.
The “correct” plug for that application is a PTF-SAE Short. (The “PT” stands for pipe thread “F” stands for fuel and the ”SAE short” insures a flush mounting)
These have a different taper (7/8 inch/foot as opposed to std pipe at ¾”)
and a different thread profile to positively seal without sealant. (An interference fit at the tip of the threads)
The thread profile is referred to as “dryseal pipe thread” this is special for fuel and
oil.
They are designed to install flush or almost flush in a standard NPT pipe threaded bore and they will also work in NPSI (national pipe thread straight internal) threads
You should have the plugs on hand before you tap the holes to insure that you get a correct fit.
To make a long story short, Fastenal stocks them; you only need to specify
¼ pipe plugs - 7/8 taper - socket head. (They will get confused with any more detail than that!)
http://www.fastenal.com
Threaded Mode
