Why Magnetic Gate Latches Can Be Problematic With Digital Mechanical Locks

A magnetic latch solves a narrow-stile problem on the day it is installed. The question is what happens when the gate moves — because gates always move.

Magnetic gate latches are sometimes paired with mechanical digital keypads when a standard tubular latch won't fit the gate frame — including 50 x 50mm aluminium sections. They can work, but they are the least forgiving latch in the range once a gate moves, and this guide gives you the honest field picture.

This guide covers:

• The two completely different products that share the name "magnetic gate latch"
• How the mortice magnetic latch works, and why narrow stiles attract it
• The gate stop: why it is required — and why it does not prevent the real problem
• What gate movement does to the latch, and our real revisit rate
• The 28mm latch we strongly prefer, and the rare cases where magnetic still wins

If the underlying problem is a narrow gate frame, start with what actually fits a narrow gate stile — magnetic is only one of four answers, and rarely the one we reach for.

Two Very Different Products, One Name

Before anything else: in Australia, "magnetic gate latch" most commonly means a D&D MagnaLatch — the top-mounted, magnetically triggered pool gate safety latch with the tall release knob. That is an excellent product doing a completely different job, and it is not what this article is about. In fact, the MagnaLatch is exactly what we recommend on pool safety barrier gates — the compliant setup is covered in pool safety barrier gates and mechanical digital locks.

This article is about the other product that shares the name: the mortice magnetic latch — typified by the BDS TML25 — a latch body that mortices into the gate stile behind a mechanical digital keypad, using a magnetically drawn pin to engage a striker in the post.

Quick check you are in the right place: if your latch sits on top of the gate with a knob you lift to open, that is the pool safety type — out of scope here. If it is buried inside the gate frame behind a keypad, read on.

What Is a Mortice Magnetic Latch?

A mortice magnetic latch uses a latch body and strike arrangement where the latch pin is drawn into position as the gate closes. In a digital mechanical gate lock setup, the keypad controls access, while the magnetic latch body engages with the striker and keeps the gate latched closed.

The BDS TML25 is the standard example: a glass-filled nylon body needing a minimum 40mm of post depth, supplied with strike packers for fine adjustment, and made in versions to suit Borg 2000/4000 series keypads and euro cylinder applications.

If you are new to battery-free keypad locks generally, start with how a mechanical digital lock works.

Where they are used: almost exclusively gates — particularly where space is limited and a standard tubular latch is not suitable. They are not normally an option we would put on a standard door.

Why They Are Used on Narrow Stiles

One piece of terminology first, because it decides the measurement. Almost everybody says "gate post", but the member that matters is the stile — the vertical edge of the gate leaf itself, where the lock mounts. The post is the fixed upright the gate latches against.

For the full set of narrow-stile answers — including the ones we actually prefer — see the short backset latch option and the guide on gate stiles and alignment.

The Gate Stop: Required, But Not a Fix

The TML25 requires a gate stop to be fitted, and it is not supplied with one. When there is nothing already on the gate, the stop we typically fit is the D&D Truclose TCGS3 gate stop for metal gates.

Here is the part worth being precise about, because it is easy to get the wrong idea. The gate stop is required for compliance and for the basic correct functioning of the gate — it gives the gate a consistent closed position instead of letting it swing through. What the stop does not do is prevent the gate and post from moving. Sag, hinge wear and ground movement carry on regardless of the stop, and it only takes slight movement for the TML25's pin to misalign and fail to throw into the striker hole.

Bottom line: fit the stop because the gate needs it — but do not expect it to protect the magnetic latch from misalignment. It cannot.

The Main Problem: Gate Movement

The biggest issue with mortice magnetic latches is that they rely heavily on accurate alignment between the latch pin and the striker.

That is fine on the day the lock is installed. The gate closes, the pin lines up, the mechanism engages and everything works as expected. The problem is what happens months or years later, when the gate naturally moves.

Common frustration: a small amount of gate sag, hinge movement, post movement or wind flex is enough for the pin and striker to stop meeting correctly. When that happens, the gate stops latching reliably — and it usually happens gradually, so the gate feels "moody" long before it fails outright.

Why Gates Move Over Time

Unlike a standard internal door, an external gate lives a much harder life — exposed to weather, wind, vibration, ground movement, hinge wear and everyday force. Even a well-built gate shifts slightly over time:

• Hinges wear or loosen, and the gate drops under its own weight
• Posts move as the ground moves
• Heat and weather work on metal and timber
• Wind pushes the gate against the latch
• People pull, slam and lean on the gate
• The gap between the gate and post changes

With a mortice magnetic latch, even a small change is enough to cause problems, because the pin and striker need to meet in the correct position — there is no bevelled face riding into place the way a conventional latch does.

What Happens When It Falls Out of Line

When the pin and striker fall out of alignment, the gate may still look closed — but the latch is not actually engaging:

• The gate bounces back open
• The latch only catches if the gate is pushed firmly
• The gate needs to be lifted or pulled into position to latch
• The lock feels inconsistent from day to day
• The gate appears closed but is not properly latched
• Adjustment work keeps being needed after installation

Misalignment is the single most common gate lock fault we see across all latch types — it earns its own entry in the installation troubleshooting chapter — but the magnetic latch is the least forgiving of it.

Warranty Call Backs: About Half of Our Installations

Across our magnetic gate latch installations, approximately 50% require a revisit to realign and adjust. Not because the product is faulty, and not because the installation was wrong — because the gate moved, and this latch tolerates movement worse than anything else we fit.

One revisit in two is not a maintenance profile we are comfortable recommending when alternatives exist — publishing numbers like this is part of our honest approach to recommendations. It is the reason we now treat the mortice magnetic latch as a last-resort option rather than a narrow-stile solution — and the reason the next section exists.

Why We Prefer the 28mm Latch

Where the gate can accept it, we strongly prefer a 28mm Borg latch over a magnetic latch — and these days we almost never install the mortice magnetic type. The 28mm backset solves the same narrow-stile problem with a conventional bevelled latch that self-latches as the gate closes, rides into its strike with far more tolerance, and does not depend on a pin meeting a hole precisely.

The 28mm latch is handed, so check which way your gate opens before ordering — the four combinations are explained in understanding door handing, with the gate-specific note in the narrow stile guide's handing section.

Our usual direction: if the gate can accept the 28mm Borg latch, that is where we look first — long before a magnetic gate latch enters the conversation.

When Would We Still Use One?

Rarely — but there are situations where a mortice magnetic latch is the practical answer. The BDS TML25DGT suits Borg 2000 and 4000 series keypads, and a euro cylinder version exists for other setups. We would consider it only when all of the following line up:

• The stile is too narrow for a standard tubular latch
• A 28mm latch solution genuinely does not suit the application
• The gate is stable and well aligned, with hinges and post in good condition
• The customer understands that future adjustment may be required

Scope note: mortice magnetic latches are for gates. They are not our option for standard doors, and they are never the answer on a pool safety barrier gate — that job belongs to the MagnaLatch pool latch covered in the disambiguation above.

When Should You Be Cautious?

We would steer away from a magnetic gate latch wherever the gate already shows signs of movement or poor alignment:

• The gate already sags or drops
• The hinges are loose or worn
• The gate moves noticeably in wind, or the post or frame is flexible
• The gate needs to be lifted to close
• The existing latch already misses the strike
• The customer expects a very low-maintenance setup

In these cases the magnetic latch may work on day one and become frustrating within months — the 50% revisit rate is built from exactly these gates.

Other Gate Factors to Consider

The latch is only one part of choosing the correct digital mechanical gate lock. Also consider whether the gate can be reached over or through — in which case a double-sided lock is the smarter choice — whether the lock faces harsh weather or coastal conditions (where marine grade earns its keep), and whether free access functions suit the site (passage mode vs holdback mode). For the full picture across every Australian door and gate type, see the door type compatibility matrix.

Related Guides

Need Help Choosing the Right Gate Latch?

Email a few photos to contact@terrys.team with your name and phone number, and we will work out whether a 28mm Borg latch, a magnetic latch or another gate lock solution is the right option — before you buy.

Disclaimer: This article is general information only. The correct gate latch depends on your gate design, stile width, post depth, frame construction, alignment, hinge condition, installation requirements and intended use. Always confirm suitability before purchasing or installing hardware.