Drill guide for combination lock mounting and method for using drill guide

Abstract

A drill guide for combination lock mounting and method for fabricating andsing the drill guide is provided. The drill guide is fabricated using several interior mounting plates bonded together to form a sufficient thickness to maintain a true level bore hole. The fabrication guide plate is attached to a secure door using a threaded clamping device extending through a lock spindle hole. Thereafter, the smaller interior holes are drilled completely through the door. Larger exterior holes are then drilled partway through the door from the outside. The door is then ready to accept an exterior combination lock plate having female studs extending into the door.

What is claimed as new and desired to be secured by Letters Patent of the united states is: 
     
       1. A drill guide for mounting a combination lock to a door having a lock spindle bore, said drill guide comprising: a guide plate having a plurality of guide holes and a larger bore hole bored therethrough, said plurality of guide holes being parallel to said larger bore hole and being distributed about said larger bore hole; and   a clamping device inserted through said larger bore hole and a lock spindle bore of a door for attaching said guide plate to the door.   
     
     
       2. A drill guide for mounting a combination lock as in claim 1 wherein said drill guide is fabricated using drill-resistant steel plates. 
     
     
       3. A drill guide for mounting a combination lock as in claim 1 wherein said guide plate comprises a plurality of plates bonded together to a thickness such that each of said plurality of guide holes can maintain alignment of a drill bit passing through one of said plurality of guide holes. 
     
     
       4. A drill guide for mounting a combination lock as in claim 1 wherein said clamping device further comprises a threaded rod having a hand-operated knob attached to a first end and a threaded knob attached to a second end, such rod having at least one washer located thereon. 
     
     
       5. A method for using a drill guide for mounting a combination lock to a door having a lock spindle bore, said method comprising the steps of: fabricating a guide plate having a plurality of guide holes and a larger bore hole bored therethrough, said plurality of guide holes being parallel to said larger bore hole and being distributed about said larger bore hole;   fabricating a clamping device that cooperates with said larger bore hole and the lock spindle bore of a door for attaching said guide plate to the door;   clamping said guide plate to an interior side of a door using said clamping device;   drilling first holes from the interior side of the door completely through the door using said plurality of guide holes;   drilling second holes partway through the door from an exterior side thereof using said first holes as guides, wherein said second holes are larger in diameter than said first holes;   removing said guide plate;   installing an exterior combination lock mounting plate from the exterior side of the door using said second holes and the lock spindle bore; and   securing an interior combination lock mounting plate from the interior side of the door to said exterior combination lock mounting plate using fasteners that project into said first holes.   
     
     
       6. A method according to claim 5 wherein said step of fabricating a guide plate comprises the step of bonding together a plurality of drill-resistant plates to form said guide plate having a thickness that maintains alignment of a drill bit passing through one of said plurality of guide holes.