blackstang14

I was about to tap the oil pan today when I looked at the diameter of the tap and the actual bolt that is to thread into my newly tapped hole. The 3/8 inch tap seem to be much smaller than the thread diameter on the bolt which is supposed to be 3/8 inch x 1/2 inch on the other end that hooks up to the actual oil line??

Any suggestions, or should this just work.

The bolt that is going to thread into the new hole has diameter of about 10/16. Do I need to have a larger tap to match this?


Thanks,
James

blackstang14

So after doing some "google research" it looks like the NPT 3/8 inch tap is actually .56 inches in diameter. I did buy an NPT but a standard 3/8 tap.

Does anyone know if you can buy the NPT tap locally or do you have to order it online?

smythge

I would think a home depot or Lowes would have NPT tap.

blackstang14

Yeah, I bought mine at lowe's, but I couldn't find the NPT style on their website or Home Depot. Sears has it but it is not in-store. I would love to be able to buy it tomorrow so I could get some work done. I might just have to wait until next weekend.

vanquish

yes i went through the same thing as you and I was confused for a while. The key is an NPT tap which would be larger in diameter than say a 3/8" drill bit.

Eduardo

i had the hardest time looking for that same tap, ended up finding it at ACE hardware.

blackstang14

Good to know its not just me. I finally ended up buying one off of EBAY for 11 bucks shipped. I went to sears, home depot, and Lowes today, the largest one I could find was 1/4 NPT. On a good note though, fuel injectors, blower/bracket/intercooler now installed. Just waiting for the tap and to arrange the piping!

The 3/8 inch NPT tap is actually .675 inches in diameter.