Determining the correct hole size for a door knob is essential to ensure that the knob fits correctly and operates smoothly. If the hole size is too small, the knob will not fit, and if it is too large, the knob will be loose and may not function correctly.
The standard hole size is 2 1/8 inches in diameter, which is the size most current locks require. However, many older doors have smaller diameter holes, and re-drilling may be necessary to fit the current standard size.
It’s essential to measure the hole size accurately and choose the appropriate knob accordingly.
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What is the Standard Hole Size for Door Knob?
When it comes to installing a new door knob, one important factor to consider is the size of the hole for the knob.
The standard size for a door knob hole is 2 1/8 inches in diameter. However, it is important to note that older doors may have smaller holes, so it is important to measure the diameter of the existing hole before purchasing a new knob.
Understanding Door Knob Hole Sizes
The size of the hole for a door knob is important because it determines the compatibility of the knob with the door. If the hole is too small, the knob will not fit properly. If the hole is too large, the knob will be loose and may not function properly.
In addition to the diameter of the hole, it is also important to consider the backset measurement, which is the distance from the edge of the door to the center of the hole. The standard backset measurement is 2 3/8 inches, but some doors may require a backset measurement of 2 3/4 inches.
Read more about what a backset on a door is.
Factors to Consider When Choosing a Door Knob Hole Size
When choosing a door knob hole size, there are several factors to consider:
- Door thickness: The thickness of the door will determine the size of the bore hole needed for the knob. A thickness of 1 3/8 inches is standard for interior doors, while 1 3/4 inches is standard for exterior doors.
- Door preparation: The type of door preparation needed for the knob will depend on the type of knob being installed. For example, a cross bore may be needed for a knob with a separate deadbolt.
- Plate size: The size of the plate that comes with the knob will also need to be considered. The plate should cover the existing hole in the door and provide a secure base for the knob.
How to Measure and Drill a Door Knob Hole
When installing a new door knob, it is important to drill a hole of the correct size and position. Here are the steps to measure and drill a door knob hole.
Tools Needed
Before starting, gather the following tools:
- Measuring tape
- Chisel
- Drill/driver
- 2 1/8″ hole saw
- Pencil
- Bar or spindle
Measuring the Door
The first step is to measure the thickness of the door. Place the measuring tape on one edge of the door and pull it until it reaches the other edge. The total measurement is the door’s thickness.
Next, measure the door’s backset, which is the length from the middle of the borehole up to the door’s edge. This measurement will determine the position of the hole.
Marking the Hole
Using a pencil, mark the center point of the hole on the face of the door. This point should be at the correct backset distance from the edge of the door.
Next, use a chisel to create a small recess at the center point. This will help guide the drill bit and prevent it from slipping.
Drilling the Hole
Attach the 2 1/8″ hole saw to the drill/driver and set the backset measurement to either 2 3/8″ or 2 3/4″, depending on the style of the door and personal preference.
Start drilling at the center point, using the recess as a guide. Once the center bit is through the door, stop. Bring the hole saw to the other side of the door and finish the bore.
Insert the bar or spindle through the hole and attach the door knob according to the manufacturer’s instructions.
If the door already has a smaller diameter hole, it may need to be re-drilled. Alternatively, a plug can be used to fill the existing hole before drilling the new one.
By following these steps, you can easily measure and drill a door knob hole of the correct size and position.
Different Door Knob Styles and Their Hole Size Requirements
When it comes to door knob styles, there are several options available, each with its own hole size requirement. Here are the most common door knob styles and their corresponding hole sizes:
Lever Handle Door Knobs
Lever handle door knobs are a popular choice for modern homes. They are easier to operate than traditional doorknobs and are ADA compliant. Lever handle door knobs typically require a 2 1/8 inch bore hole, with a backset of either 2 3/8 inches or 2 3/4 inches.
If using one, it’s important to determine which directon your lever handle should be oriented.
Mortise Locks
Mortise locks are a type of lock that is installed within the door itself, rather than on the surface. They are commonly used in commercial buildings and high-security areas. Mortise locks require a 1 1/2 inch bore hole, with a backset of either 2 1/2 inches or 2 3/4 inches.
Deadbolts
Deadbolts are a type of lock that provides extra security to a door. The standard size for a deadbolt is a 2 1/8 inch bore hole, with a backset of either 2 3/8 inches or 2 3/4 inches. Deadbolts come in both single and double cylinder options, with the latter requiring a larger hole to accommodate the keyhole.
Electronic and Smart Locks
Electronic and smart locks are becoming increasingly popular due to their convenience and security features.
They typically require a 2 1/8 inch bore hole, with a backset of either 2 3/8 inches or 2 3/4 inches. However, some electronic and smart locks may require additional drilling for wiring or batteries.
Did you know you can even get smart locks for outdoor gates?
Dummy Knobs
Dummy knobs are a type of door knob that do not have a latch or lock mechanism. They are often used for decorative purposes or to cover up holes in a door. Dummy knobs require a 2 1/8 inch bore hole, but do not require a backset measurement.
Amazon have a large selection of dummy door knobs in all shapes, sizes and colours, take a look here.
FAQ’s
Final Thoughts
When it comes to door knobs, it’s important to know the standard hole size and other related information to ensure proper installation and functionality.
The standard size for a door knob hole is 2 1/8 inches in diameter, but older doors may have smaller holes that require re-drilling. It’s also important to consider the backset, grip, and cylinder type when choosing a door knob.
When it comes to door locks, there are many options available, including deadbolt locks and universal door handles. Kwikset and Schlage are popular brands known for their quality and durability. It’s important to choose a lock that provides the right level of security and control for your needs.
In terms of door knob shapes and styles, there are many options available, including round, square, and oval shapes. It’s important to choose a style that complements your home’s décor and fits your personal preferences.
