What drill bit size for a 1/2" brass pipe bulkhead in cooler?

[hezagenius]

My cooler doesn't have a spigot hole so I need to drill one. I have all the parts for a 1/2" bulkhead. I bought a 1/2" drill bit but this is clearly too small and I can't find the O.D. of the 1/2" brass nipple. It is a Watts A-836 1/2" x 1 1/2" brass nipple. Anyone know what size drill bit or hole cutter I need?

 

[Bobby_M]

1/2" pipe is 1/2" inside diameter and 3/4" outside.

 

[BackAlleyBrewingCo]

I'd recommend a 3/4" step bit [Harbor Freight]:

 

[hezagenius]

Thanks. That step bit looks like the ticket!