What gate lock size do I need?

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If you have decided to source your own gate lock for your new gate, there are some terms and dimensions you will have to know. One of these is of course the size of the lock. Although you might not have thought that locks come in different sizes, they absolutely do. But there is more to it than that, because the way they are measured actually varies from lock type to lock type as well.

Don’t worry! We are here to help.

Find out how to measure your gate frame properly depending on the lock type so you can get the correct lock the first time around.

Below, we’ll cover how to measure the gate frames for:

Weld-in locks:

Weld-in locks are popular because they sit flush within the gate frame. It’s therefore very important you choose the right size. Weld-in gate lock sizes are measured based on the width of the gate frame.

If your gate measures 40mm width, you need to get the locks with the same sized lock box/case.

how to measure a weld in gate lock

Common sizes for weld-in locks are: 30mm, 40mm, 50mm and 60mm. Check out the full range of weld-in locks here.

Bolt-on gate locks:

As opposed to weld-in locks, bolt-on locks are fitted through the gate frame with fixing bolts. The width is therefore not relevant when fixing these. Instead, the size depends on the thickness of the gate frame.

The size of the lock itself doesn’t change. Instead, it’s the length of the latch bolt that does. At Signet Locks, we therefore group our bolt-on locks in two size categories: 10-30mm and 40-60mm gate frame. The latch bolt for a gate with a 10mm flat bar won’t work for a 60mm box section. As we always advise the latch bolt sticks out 15mm, the latch bolt has to be longer for the bigger gate frames.

This makes it easier if you accidentally order the wrong sized lock. All it takes is getting the right latch bolt, which can be easily replaced. Just get in touch with our sales department and they can sort that out!

You can check the lengths and movements of the latch bolts in this article.

Surface-fixed locks:

Surface-fixed locks are commonly fitted to solid infill gates like timber or composite gates. You therefore won’t see different sizes of these locks here on the Signet website as it doesn’t change. What does change is the fixing screws used to fit the locks, as the size depends on the width of the gate.

The Superlatch (SLDS) is a good example of this. With the standard fixings supplied with the lock, you can install it on gates up to 75mm wide. But for any gates thicker than that, we offer an extension kit which makes the SLDS suitable for gates up to 140mm wide!

The lock stays the same, but the fixings required get longer.

Mortice locks:

At Signet Locks, we also have a range of mortice locks. Sitting within the gate frame, these locks are inconspicuous. Mortice locks are one size and fits most gates. As standard, our mortice locks will fit any gate of 40mm width or more without the need for any modifications.

If you have a thinner gate, you may need to do alterations so that the lock can fit in, or alternatively why not look at one of our other lock options which may suit your needs better.

Mortice locks also often mention the backset. This refers to the distance from the front of the lock to the centre of the spindle/cylinder hole. You’ll need to drill a hole for the cylinder and handle, so it’s important to know this measurement and get it right. It’s even more important if you have an existing lock you’re replacing as the holes have to match up.

What size gate lock do I need?

The size gate lock you need depends on the type of gate lock you want. Where bolt-on locks measure the thickness of the gate, weld-in locks, surface-fixed locks and mortice locks are sized based on the width of the gate frame.

Most gate locks sizes will have the gate frame size stated to help you.

As always, if you have any questions, you’re always welcome to send us an email or give us a call. Our helpful sales and customer service teams are ready to assist.