As an engineer or engineering student, you know that every little thing matters when planning and building a project.
One small mistake in math can cause delays that cost a lot of money, put people in danger, or cause inspections to fail.
Backset, which is the horizontal distance from the face of a lock or latch to the center of the keyhole, knob, or lock cylinder, is an important but often forgotten detail in the building industry.
Even though it might not seem like much, knowing how important backset is in door hardware can make a big difference in how safe and secure a building is.
In this article, we will talk about everything you need to know about backset, including why it is important and how to measure and adjust it correctly.
So get your measuring tape and get ready to dive into the world of backset engineering.
Introduction to Backset
Formal definition:
The horizontal distance from the face of a lock or latch to the center of the keyhole, knob, or lock cylinder.
Backset is a very important measurement when installing locks and latches on doors.
It is the distance from the edge of the door to the middle of the cross bore hole that most locks need to be installed.
You need to know the right length of your door latch because if you order the wrong backset, you could end up with a latch that is too long or too short, making it impossible to mount your lock.
Standard Backset Sizes
Most doors today are prepped with standard sizes, like a 1" cross bore hole, 2 1/8" bore hole.
They are also prepped to fit either a 2 3/8" or 2 3/4" backset.
In the United States, 2-3/8" and 2-3/4" are the two most common backsets.
It is important to note that exterior doors are more likely to have a 2-3/4" backset than interior doors.
The length of the backset on a commercial (DIN) lock case is 60mm.
Take a Risk: Disregard Backset in Door Hardware and See What Happens
Still hard to understand? Let me change the point of view a bit:
If you want to add some danger and excitement to your life, you should totally ignore how important backset is in door hardware.
Who needs to measure that "insignificant" distance from the face of a lock to the center of the keyhole? Who cares if your locks do not work right or if your doors can be opened easily? After all, who wants to be safe and sound when you can live on the edge? Just do not put the blame on us if your doors do not work right or if your building does not pass inspection.
Okay, that was just a joke made to look like a TV ad.
Now let's go back to the explanation.
Measuring Backset
When putting new locks or latches on a door or replacing old ones, it is important to measure the backset.
The backset is the distance between the center of the cross bore and the edge of the door.
It tells how long a door latch should be.
In North America, 2 3/8 inches and 2 3/4 inches are the most common backset measurements for door hardware.
How to Measure Backset
You will need a measuring tape or ruler to figure out the backset.
If your door does not have any hardware, measure from the edge of the door to the center of the borehole.
It is sometimes easier to measure from the edge of the door to the highest point on the borehole.
If your door already has hardware on it, take the hardware off and measure from the center of the cross bore to the edge of the door.
Be careful not to make common mistakes when measuring or adjusting backset, like ordering the wrong backset or putting the new lock in the wrong place.
Standard Backset Measurements
In North America, 2 3/8 inches is the most common backset size for door hardware, but 2 3/4 inches is also quite common and is often used on exterior doors.
It is important to measure correctly because if you order the wrong backset, your latches will be too long or too short, and you will not be able to mount your door hardware.
Some brands of door hardware, like Schlage, Weiser, Kwikset, Sure-Loc, and Weslock, come with backset latches that can be adjusted.
This makes it easy to order.
The default backset size for Nostalgic Warehouse is also either 2 3/8 inches or 2 3/4 inches.
Access Hardware says that the center-to-center length of a stretto, sideplate lockset, or entry set is measured from the middle of the top handle.
Emtek's Baden, Davos, and Lausanne entry sets, for example, all have the same design but have different names.
Other Factors to Consider
Another thing that can change the backset measurement is the thickness of the door.
Most modern front doors are 1-3/4 inches thick, while many interior doors are 1-3/8 inches thick.
But this can be different, since doors in older homes may be thinner and doors in newer homes are often thicker.
To be sure of accuracy, you must measure more than once.
When installing door hardware, it is also important to check things like the crossbore diameter and latch bore diameter in both the door and the jamb.
Alternative Methods for Measuring Backset
You can also measure backset with a measuring tape or a ruler, but there are other ways to do it.
Some manufacturers include information about backset measurements in the specs for their products.
You can also use a template that fits the size of your lock and lines up with the hole in your door.
Adjusting Backset
Most door latches on the market today are adjustable, so you can change the distance between the door and the latch from 2-3/8 inches to 2-3/4 inches.
But if the backset measurement is wrong for the hardware being installed, it can be changed in a few easy steps:
Find the tab on the top of the door latch.
- Depress the tab.
- Depress the latch bolt.
- Pull out the latch bolt.
- Turn it around so that it faces in the opposite direction.
- Reinsert it into its hole with either a 2-3/8 inch or 2-3/4 inch backset.
If you want to change the backset measurement to something other than 2-3/8 inches or 2-3/4 inches, you might have to buy a new latch with the backset measurement you want.
Different Types of Door Locks
There are different kinds of door locks, such as deadbolts, sideplate locksets, and door knobs.
Each type serves a different purpose and has its own safety features.
Deadbolts are the most secure way to lock a front door, and there are three main kinds: single, double, and vertical.
Single-cylinder deadbolts can be opened with a key from just one side.
Double-cylinder deadbolts, on the other hand, need keys from both sides.
Vertical deadbolts work like single and double deadbolts, but they are installed vertically instead of horizontally.
Sideplate locksets have a keyed deadbolt, a knob or lever, and a solid decorative backplate that connects the two.
You can also get them with two-point locks, which have a keyed lock on the knob or lever as well as the deadbolt.
There are different kinds of door knobs, like privacy, keyed entry, passage, storeroom, and half-dummy.
Privacy door knobs are made for inside doors and can be locked and unlocked from the outside with an emergency key or from the inside with a push button or turn button.
Keyed entry door knobs often have different security features, like security grading, that make them safer.
Alternative Methods for Adjusting Backset
There are other ways to change the backset measurement than by adjusting the latch itself.
For instance, you can use a template that fits the size of your lock and lines up with the bore hole in your door.
You could also look at the manufacturer's specifications for their products, which may include measurements of the backset.
Backset and Door Safety
The backset measurement is an important part of installing door hardware because it tells you how long the door latch should be.
Even though backset may not directly affect how safe a door is, a smaller backset can make a door more likely to be broken into.
So, the standard backset for residential doors is 2 3/8 inches or 2 3/4 inches, and the standard backset for commercial doors is also 2 3/4 inches.
This is to make sure that the door works well and is secure.
How to Adjust the Backset on a Door Latch
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Use cases
| Used in: | Description: |
|---|---|
| Residential Doors: | When installing locksets or deadbolts on residential doors, backset is an important thing to think about. Different locksets and deadbolts may need different backset measurements, so it is important to measure the distance between the face of the door and the center of the lockset or deadbolt to make sure the hardware fits right and works as it should. |
| Commercial Doors: | When installing exit devices or panic bars on doors in commercial buildings, backset is one of the most important things to think about. In case of an emergency, these types of devices are meant to provide a safe and easy way out, so it is important that they are installed with the right backset measurement. |
| Access Control Systems: | Backset is also important when putting in a card reader or keypad for an access control system. Most of the time, the design of these systems needs to include a backset measurement to make sure that the card reader or keypad is installed in the right place in relation to the lockset. |
| Cabinet Doors: | Backset is another thing to think about when putting hinges or knobs on cabinet doors. In this case, the backset measurement is important to make sure that the hardware is put on the cabinet door at the right distance from the edge. |
| Gates and Fences: | Backset is one of the most important things to think about when putting locks on gates and fences. The backset measurement is important to make sure that the lock or latch will line up correctly with the gate or fence and that the gate or fence will close and lock securely. |
Conclusion
In conclusion, you can not say enough about how important backset is in door hardware.
Every part of backset is important to the design and building process, from the safety and security of a building to the way a door works.
As an engineer or engineering student, paying attention to even small details like backset can make all the difference in how well your project turns out.
By knowing what affects backset and having the right tools and methods for measuring and adjusting it, you can make sure that your doors work as they should and keep building occupants as safe and secure as possible.
So, the next time you put in door hardware, remember how important backset is and how it can affect how well your project goes.
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