Juice doc says to drill 5/16 and tap with 1/8" NPT tap....????





I s this correct a smaller 1/8" tap would fall through a 5/16" hole????http://www.dieselplace.com/forum/smileys/Ermm.gif








What am I missing?????

I haven't looked at my reference chart, but that sounds close.


Your confusion arises from the fact that NPT (National Pipe Thread) is referenced such that pipe fittings with tapered thread bodies, refer to the size of the hole in the fitting, not the outside diameter of the fitting.


So a 1/8" pipe fitting would have to have a larger diameter hole drillied in order to accomodate the fitting.

Yep! That's right!http://www.dieselplace.com/forum/smileys/Approve.gif

I just installed my EGT on my rig yesterday, everything went smooth, I drilled a pilot hole and then used a 21/64 drill and a 1/8 in pipe tap, took longer to R&R inner fender.


HTH


Ron

ThaNKS...i DIDN'T CATCH the NPT sizing..





Your right about the fender R&R..those expandable trees are a PITA to get out and still be reusable.