How to Fit a Reversible Tubular Latch

Make sure your door knob opens the correct way by following these tips for fitting a reversible architectural tubular latch.

This guide explains the component parts of a tubular latch, the key sizing terms and some useful installation advice to help prevent common fitting issues.

Component Parts of a Tubular Latch

The most important measurements to understand when choosing a tubular latch are the backset and the case size.

Backset

The backset is the distance from the forend plate to the bore hole through which the mortice bar is fitted.

Case Size

The case size is the overall measurement from the forend plate to the end of the tubular latch.

Choosing the Right Tubular Latch Size

When choosing your tubular latch, first decide how far from the edge of the door your door knob will be fitted.

A 4-inch case length is generally recommended for door knobs, as it helps prevent your knuckles from catching on the door surround when opening and closing the door.

However, the longer case length may not always be suitable, especially on doors with glass panels. In these cases, a 3-inch latch is often the better option.

How to Prevent Your Tubular Latch Sticking

When a tubular latch is fitted, it may sometimes stick or make a grinding noise when the mechanism is turned.

This is usually caused by the mortice hole in the door being cut slightly too small. The hole needs to provide enough clearance for the tubular latch mechanism to move freely.

If the mechanism is too tight within the timber, the moving parts can bind against the inside of the door and prevent smooth operation.

Installing the Tubular Latch the Right Way Up

Architectural tubular latches have a reversible latch or catch, allowing them to be fitted to both left-hand and right-hand opening doors.

Most tubular latches have a helpful “This Way Up” label engraved onto the case. When installing the latch, make sure this marking remains the right way up.

To ensure your door knob operates correctly and turns clockwise away from the edge of the door, rotate the protruding latch or catch by 180 degrees. Do not invert the entire tubular latch.

You can test this before installation by inserting the mortice bar and fitting the door knob to check which way the latch or catch needs to be positioned for your door.

Key Points to Remember

1. When cutting the mortice hole, allow enough clearance for the mechanism to turn freely without being squeezed against the timber.
2. Choose the correct tubular latch size by considering the overall case length and backset.
3. Always take note of the “This Way Up” marking on the latch case.

We hope you found this video and guide useful when choosing and fitting an architectural tubular latch with a door knob.

You may also find our guide on how to fit a door knob with concealed fixings helpful.

Browse our range of architectural and standard tubular latches and sash locks.

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