The standard sized bore hole is 2 1/8" in diameter. Through the edge of the door there is a 1" cross bore that extends from the edge of the door through the bore hole. (This cross bore is where the latch is installed).
Most deadbolts need a hole 2-1/8-inches in diameter for the body of the lock to fit into the door. The bolt on a typical deadbolt requires a 1-inch hole in the edge of the door.
Choose the Right Lock to Fit Your Door
Usually, the backset measures 2 3/8-inches or 2 3/4-inches. Cross (or edge) bore: The small hole along the edge of the door frame, usually measuring about 1-inch in diameter.
3 Bore the doorknob hole through the face of door using a 2 1/8-inch hole saw; drill halfway through from each side. 4 Use a 1-inch hole saw to bore latch hole in door edge.
For standard handles or door knobs I drill a 16mm hole in from each side of the door - being careful not to go all the way through (for some door handles and knobs you need to use a hole saw to drill a large 2 1/4" hole). Next, I use a 25mm flat wood bit to drill into the centre of the doors edge.
The best drill bits for drilling locks are either tungsten carbide-tipped drill bits or cobalt drill bits. Tungsten drill bits can be used to drill lock components made from bronze alloys, cast iron, alloyed steel, and hardened steel.
The latch bore is the small hole on the edge of the door for the latch itself. The standard measurement for a bore hole is 2 1/8 inch in diameter and the standard measurement of a cross bore is 1 inch in diameter.
Not all doorknob or lever sets are made for the 2-1/8" bore hole. There are some, like the Baldwin Estate Series hardware that use a small 3/4" bore hole. If your bore hole is as small as 3/4", give us a call and we can help you find a lock that will fit your door.
Most modern doorknobs will fit most standard doors, but this is not a universal law, so doorknobs are not universal, so you will need to measure the borehole, backset, and door thickness before you install your doorknob.
There are several different types of door locks. The main types you are likely to have on your doors are: Five-lever mortice deadlocks. Key-operated multi-point locks. Night latches/rim locks.
Tubular Latches, Sashlocks, Deadlocks and Bathroom Locks are available in varying lengths and sizes to suit your requirements or match existing ones already fitted in your doors.
The standard hole size for cylindrical locksets is 2 1/8″. Cylindrical is the most common type in residential settings. The standard backset (distance from the edge of the door to center of hole) is 2 3/8″ or 2 3/4″, with 2 3/8 being more common. Most locksets have an adjustable latch that can be used for both.
Be sure to use the correct size drill bits specified in the lock set instructions, though most standard deadbolts require a 2 1/8-inch hole saw for the lock bodies and a 1-inch spade bit for the sliding bolt assembly.
The latch bore, also known as the edge bore, is the hole drilled from the side of the door into the cross bore to allow the latch of the lock to be installed and to accommodate the sliding of the deadbolt. The diameter of the latch bore is generally 1” to accommodate bolts from either mechanical or electronic locksets.
The standard size for a door knob is a diameter of 2 3/8 inches or 2 3/4 inches and these will fit doors that have a thickness from 1 3/8 inches to 1 3/4 inches.
The door backset is the distance from the edge of the door to the center of the 2-1/8-inch bore hole for the door knob, lever or deadbolt. In the United States, there are two common backsets for residential door locks: 2-3/8 inches. 2-3/4 inches.
Many door knobs have a hole on the side near the narrow end that is close to the door. This is a release so the knob can be removed. Pressing a paperclip into the hole will allow the knob to be pulled off. You'd want to do this with lever style handles if they need to be reversed to point toward the hinge side.
Most deadbolt assemblies are a standard size, but you'll need to read the instructions or measure the assembly to choose the correct hole saw bit.
Door widths which are considered standard usually come in sizes of 2/6 (30”), 2/8 (32”) and 3/0 (36”). Standard door heights are 6/6 (78”) and 6/8 (80”).
Determining the backset and overall length can be done by removing the existing latch and taking the dimensions. If the door handle or knob is still in place and you'd rather not remove it then you can measure from the edge of the door to the centre of the spindle hole (centre of the handle/knob).
We refer to the round holes where the door lock is installed as “bore holes” (brush up on your door hardware terminology here.) Most doors have one, two or three bore hole. If the door has no bore holes, you can simply install a non-turning or “dummy” knob or lever that serves as a decorative door pull.
The backset is the distance from the edge of the door to the center of the bore hole. There are two common backsets for residential door locks: 2-3/8″ and 2-3/4″.