What size hole and tap

What size hole and tap do i need for a John guest fitting ?
The fitting is threaded on one end .
The size of the fitting is 1/4OD (1/8CTS) 1/4 MIP

 

Here's a chart I found for NPT (National Pipe Thread) taps.

Some of the drills are odd sizes, but you can usually buy the tap and drill as a pair at most Harware store.

NPT Size Tap Drill Size (in.) (Decimal) (in.)
1/16 - 27 , "C" , (0.242)
1/8 - 27 , "Q" , (0.332)
1/4 - 18 , 7/16 , (0.438)
3/8 - 18 , 9/16 , (0.562)
1/2 - 14 , 45/64 , (0.703)
3/4 - 14 , 29/32 , (0.906)
1.0 - 11 1/2 , 1 9/64 , (1.141)
1 1/4 - 11 1/2 , 1 31/64 , (1.484)
1 1/2 - 11 1/2 , 1 23/32 , (1.719)
2.0 - 111/2 , 2 3/16 , (2.188)
2 1/2 - 8 , 2 39/64 , (2.609)
3.0 - 8 , 3 15/64 , (3.234)

Hope this helps
Mike
Edit: for some reason I could not get the columns to align so I put a comma between each column. The First column is pipe thread size - threads per inch