A 
system and method of 
cutting a core out of a finished surface for 
keyhole excavation provides a 
truck with a 
turret to which a support arm supporting the cutter 
assembly is mounted, and a stabilizing member remote from the 
turret, which allows the 
turret to be rotated about its complete arc of motion while stabilizing the support arm at any desired position about the 
truck. In a first embodiment the invention comprises an upstanding support rim affixed to or integrated into the 
bed of the 
truck. In a further embodiment the invention comprises a support member affixed to the horizontal arm and supported by the truck 
bed. This makes the 
keyhole excavation procedure 
safer and more precise, and allows a larger-depth 
cutting head to be used in order to penetrate thicker finished surfaces. In the preferred embodiment the cutter head is provided with a 
pilot which creates a 
pilot hole in the core that facilitates removal, manipulation and replacement of the core, and improves the integrity of the reinstated core.