TF Lock for Doors with Limited Keyhole-to-Frame Clearance

This guide explains when and why you must choose the TF lock.

TF is specifically designed for doors where there is very limited space between the keyhole (spindle centre) and the outside door frame.

Because TF is extremely slim, it is suitable for installations where other models may not physically fit.

You should consider TF if:

Your door has a very small distance between the centre of the keyhole and the outside door frame
Your existing lock sits very close to the frame
You have limited clearance due to door design
Other locks appear too wide to fit safely

Critical Measurement Requirement

Minimum Required Space for TF:

The minimum distance required from the:

Centre of the keyhole → to the outside door frame

after calculation must be: 23mm or more

If the final measurement is less than 23mm, TF will NOT fit.

How to Calculate If TF Will Fit

Step 1 – Measure the Backset

Backset is: The distance from the edge of the door to the centre of the keyhole

Measure this in millimetres (mm).

Step 2 – Measure the Rebate

Rebate is: The amount the door sits inside or overlaps into the frame

Measure the rebate in millimetres.

Step 3 – Subtract

Calculate: Backset – Rebate = Available space

This result must be 23mm or greater for TF to fit.

If it is under 23mm, TF cannot be installed.

Why TF Works in Tight Spaces