American Tool 17105 Carbon Door Lock Installation Kit
"CARBON DOOR LOCK INSTALLTION KITSelf centering jig provides perfect hole alignment for face and edge holes. Plus, it allows for easy enlargement of smaller existing holes (common on older doors.) Fold over tabs adjust for 1 3/8 and 1 3/4 thick doors. Deep 2 1/8 hole saw bores completely through 1 3/4 doors. Allows for resizing of existing holes. Mounting holes secure the jig and match the latch plate holes. 1 hole saw cuts a straight, clean hole."