Largest centre bit I've ever come across

[rob1693]

No makers mark on large bit 2 1/2 inch in diameter
Any one any idea what the other centre bit at the side is used for

 

[adidat]

Thats a whopper could the other one be a counter bore for sinking screwheads ect??

Adidat

 

[Rorschach]

Piloted counterbore, probably for coach bolts looking at the proportions.

 

[Phil Pascoe]

The large one might be a cooper's tool?