drill bit size for 3/8" NPT

[Lammy]

I bought a 3/8" NPT tap so I can use 1/2" 3/8" NPT barbs in my DIY water block. How big does the bit drilling the holes need to be?

I was told 37/64, does that sound right?

[NeoMoses]

37/64" is right.

[Suma]

sry to bump in what's NPT?

[NeoMoses]

NPT = National Pipe Taper. It's a tapered thread used in many plumbing applications.

[Suma]

thx neo.