You can get more work done in less time by using a Century Drill & Tool Door Lock Set. Fit for the task, the 4 pc. door lock set cuts up to 1-1/2-in. deep holes to help your work just fly by! The set is comprised of professional bi-metal hole saws with cobalt high-speed steel teeth electron welded to shatterproof, shock-absorbing alloy bodies. No one likes overspending on tools to make other tools work, so this door lock set can be used in portable electric drill machines, lathes and milling machines.