core drill bit

[Norman Watts <Norman_Watts@zzzzzzz>]

i've seen workers here on campus hold big (like 5 inch) core bits in
concrete using a device that held a big drill and was in turn held down
onto the surface with a small pump. the cooling water spilling over
provide a seal and the pump sucked the whole rig tightly enough onto
the sidewalk that the drill worked unattended, under its own weight it
seemed. The rpms were really low, almost visible.

Norman Watts, Ph. D.
National Institutes of Health
50 South Drive, Rm. 1509
Bethesda, MD 20892-8025
Phone: (301) 402-3418
Fax: (301) 480-7629