Scar plates are one of those accessories that rarely get explained properly. They don't appear on most lock specification sheets, they're not mandatory for every install, and yet Terry's team reaches for them on a large proportion of retrofit jobs. Ask a locksmith why and the answer is usually blunt: the door was drilled for something else, the new lock doesn't cover the old holes, and the client doesn't want their new smart lock sitting on a door that looks like it's been attacked with a chisel.

This guide covers scar plates specifically used in smart lock installations — the thin stainless steel or powder-coated cover plates that sit between the lock escutcheon and the door face. General cylindrical hardware scar plates are a separate category not covered here.

This guide covers:

• What a scar plate is and what it actually does
• The scenarios that trigger the need for one
• Why dimensions and cut-out geometry matter more than most people expect
• Material and finish selection — SS304, mild steel, aluminium
• Fire door scar plates — a genuinely different specification
• A brand-by-brand breakdown of every scar plate Terry's stocks
• Gate and aluminium door applications

For background on fire door compliance when fitting any smart lock hardware, see the Fire Door Smart Locks chapter of the Buyer's Guide for core type identification.

What Is a Scar Plate?

The Basic Concept

A scar plate is a flat metal plate — typically 1.5 mm to 2 mm thick — that mounts flush against the door face, behind the lock body. The lock's escutcheon then overlays the scar plate, sandwiching it against the door. In a finished installation you usually can't see the scar plate at all; it's hidden beneath the lock. What you can see is the door looking clean and undamaged around the lock perimeter.

The name comes from the function: the plate covers the "scar" — the visible holes, gouges, drill marks, or timber damage left when old hardware was removed. The industry also uses the terms cover plate and renovation plate interchangeably, though "scar plate" is the dominant term in the Australian trade.

Three Functions

• Cosmetic: Concealing old fixing holes, mark-up lines, or timber damage from the previous lock. This is almost always the primary driver.
• Structural: Distributing clamping force across a larger area of door face, reducing timber compression around fixing screws — particularly relevant on older, softer timber doors.
• Security: Adding a steel barrier around the lock mounting area, making it marginally harder to attack the door face at the escutcheon perimeter with a drill or chisel.

Scar plate vs escutcheon: A scar plate is not the same as an escutcheon. The escutcheon is the decorative surround that ships with the lock and covers its own fixing holes. A scar plate is a separately-sourced accessory that goes between the escutcheon and the door face to handle what the escutcheon alone cannot cover.

KAS NEO smart lock installed over a large scar plate — the plate covers the original prep and provides a clean surround for the escutcheon.

When Do You Need a Scar Plate?

Primary Triggers

Replacing a KNK entrance set with a digital lock is the single most common trigger. KNK-style entrance sets leave behind a large round bored hole and fixing screw positions that don't align with the new digital lock's escutcheon footprint. A Borg 2000 or 5000 series digital lock has a much taller and narrower escutcheon than a typical entrance set rose — the old hole pattern is frequently exposed above or below. Borg makes matched scar plates specifically for this scenario.

Upgrading from one digital lock to a different digital lock is the second most common case. Different brands — and even different models within the same family — have different escutcheon dimensions. The new lock covers its own prep, but earlier drilling for the previous lock's fixing centres may now be visible.

Other Common Situations

• Accidental drill damage — the hole went slightly off-centre or a chisel slipped. A scar plate covers it cleanly.
• Oversized prep holes — some older doors were prepared for large-format mortice locks; when a modern digital lock drops in, the escutcheon perimeter may not fully cover the hole.
• Multi-tenant or commercial buildings with a history of hardware changes — doors in strata, hotels, and offices often bear evidence of multiple previous hardware generations.
• Visual finish matching — on higher-end projects, a scar plate in the same finish as the lock creates a considered design surround rather than a concession.

Check both sides: Scar plates are needed on each door face independently. The internal side is frequently overlooked and often has its own visible damage from the previous installation. Always inspect both faces before deciding whether a plate is needed and on which side(s).

Why Size and Shape Matter

Two Critical Dimensions

The plate must cover the damage. Outer dimensions need to fully overlap the old hole pattern on all sides. If previous hardware left damage extending 160 mm top-to-bottom, a 150 mm plate won't do the job. Smart lock scar plates range from around 180 mm to 400 mm in length and 60 mm to 95 mm in width.

The plate must not interfere with the lock. Many scar plates include precision cut-outs sized for the lock body or latch mechanism. The Lockton PS-REC-36 for the Elev36 has a 200 x 25 mm rectangular cut-out that allows the Elev36's lock body to pass through cleanly. Use a generic plate without the correct cut-out and the lock simply won't mount correctly.

Plate Thickness

Smart lock scar plates are almost always 1.5 mm thick. Some McGrath plates — specifically the Stafford, Bardon, and certain Stafford/Hamilton shared models — are 2.0 mm. The thicker versions are required where fire rating is involved or where the manufacturer specifies structural grade steel. Using a 2.0 mm plate where 1.5 mm is specified is usually fine. Using a 1.5 mm plate where the lock's fire certification assumes 2.0 mm is not acceptable.

Lockwood Cortex CTX530 scar plates — the oval slots are sized to clear the escutcheon fixings. Dimension and cut-out geometry are lock-specific, not interchangeable.

The practical rule: Always specify the scar plate by the lock model it's designed to suit, not by approximate dimensions. Most brands design their plates to match fixing centre patterns, not just outer dimensions. Specifying by lock model avoids both fit and fire compliance issues.

Materials and Finishes Explained

The Three Materials

304 grade stainless steel (satin finish) — the most common material across the range, used by McGrath, Borg, Lockwood, Lockton, and ADI. Grade 304 offers good corrosion resistance. Appropriate for coastal environments, wet areas, and exterior doors. The satin finish is mechanically brushed, resistant to fingerprints and minor scratches. If you're installing on an exterior door in a Queensland climate, 304 grade satin stainless is the correct default choice.

Mild steel with powder-coat (matt black) — used in several McGrath matt black variants and some Borg plates. Powder-coated mild steel is not corrosion resistant once the coating is penetrated. A chip on an exterior door in a humid or coastal environment will rust within months. Matt black powder-coated plates are appropriate for interior doors or sheltered exterior positions only. Do not specify for exposed exterior doors in coastal Queensland.

Aluminium — appears in the McGrath Windsor plate (MLSPWINSPALU) at 265 x 95 mm. Lightweight, naturally corrosion resistant, and common in aluminium door fabrication. Primarily designed for aluminium-framed doors where matching the substrate material aids installation and visual consistency.

Material Selection at a Glance

Finish Matching

Lock hardware is increasingly specified in matt black. If the lock escutcheon and lever set are matt black, a stainless scar plate will be visible as a material discontinuity. Where a matt black plate is available for the relevant lock model (Borg 2000/5000, McGrath Hamilton, McGrath Windsor/Albion, Lockton Elev36), specify it for a clean result.

Scar Plates on Fire Doors

The Requirement

Fire door installations introduce a requirement that most people don't anticipate: the scar plate itself must be fire rated for the door type it's being fitted to. This is a tested requirement under AS/NZS 1905.1. If a fire door's certified hardware log doesn't include the scar plate, fitting one may void the door assembly's fire rating.

Fire-Rated McGrath Scar Plates

Several McGrath scar plates carry a 2-hour fire rating when installed on Firecore and E-Core door assemblies as part of a compliant lock installation. The fire-rated models are:

• MLSTASP300X70SS — 300 x 70 x 2 mm satin stainless, suits Stafford/Hamilton
• MLHAMSCARPLAT85SSS — 300 x 85 x 1.5 mm SS304, suits Hamilton
• MLHAMSCARPLAT85MBLK — 300 x 85 x 1.5 mm mild steel matt black, suits Hamilton
• MLHAMSCARPLATSSS — 300 x 70 x 1.5 mm SS304, suits Hamilton
• MLHAMSCARPLATMBLK — 300 x 70 x 1.5 mm mild steel matt black, suits Hamilton
• MLBARDSP350X85SS — 350 x 85 x 2 mm SS304, suits Bardon

Brands Without Fire Ratings

The Borg plates, Lockton plates, Lockwood CTX plates, and ADI plates do not carry fire ratings and must not be used on fire doors unless the relevant door manufacturer has specifically approved them in writing as part of a tested assembly.

Queensland fire door rule: Any modification to a fire door — including fitting a scar plate — must either maintain the existing fire rating using tested components, or be explicitly approved by the door manufacturer. In strata buildings, body corporate approval is also required. Never fit a non-rated scar plate to a fire door assuming it's a cosmetic-only change. See the fire door core types section of the Buyer's Guide for core identification.

Identifying a Fire Door

Check the compliance tag on the hinge edge or top edge of the door. It will show the fire resistance level and core type. See the fire door types and certification blog for a walkthrough, and Terry's fire rating certificates page for official McGrath scar plate fire test certificates.

Brand-by-Brand Guide to Scar Plates

Borg Scar Plates

Borg makes scar plates for two lock families — the 2000/4000 series and the 5000 series — explicitly designed for replacing KNK entrance sets. Neither is fire rated.

• BLSPLT / BLSPLTMB — 180 x 65 x 1.5 mm. Suits Borg 2000 and 4000 series. Satin stainless (BLSPLT) and matt black powder-coat (BLSPLTMB). Supplied as a pair. View BLSPLT  |  View BLSPLTMB
• SPBL5001 / SPBL5001MB — 198 x 68 x 1.5 mm. Suits Borg 5000 series. View SPBL5001  |  View SPBL5001MB

McGrath Scar Plates

McGrath has the broadest scar plate range Terry's stocks, covering five lock families. Several carry 2-hour fire ratings on Firecore and E-Core doors. All supplied as pairs.

Borg BL2301SC on a laser-cut aluminium gate — the scar plate covers the notch cut into the gate rail for the lock body. Terry's installation, Labrador.

Lockton Scar Plates

Lockton scar plates include precision internal cut-outs sized for the lock body — the lock mounts through the plate rather than over it.

• PS-REC-36-SS / PS-REC-36-BLK — 377 x 70 x 1.5 mm with 200 x 25 mm rectangular cut-out. Suits Lockton Elev36. Sold individually (one plate per pack — order two for both faces). View PS-REC-36-SS  |  View PS-REC-36-BLK
• PS-REC-TNC-BLK — 225 x 69 x 1.5 mm, suits Lockton Elev64 and select Gainsborough, Lockwood, and Lane entry locksets. View PS-REC-TNC-BLK

Lockton plates sold individually: The PS-REC-36 series is one plate per pack — not a pair. If you need both door faces covered, order two units. Every other scar plate in the range ships as a pair.

Lockwood / ADI Cortex Scar Plates

• CTX-SSPLT-3772 — Lockwood branded, suits Cortex CTX3772. Satin stainless, sold as a pair, 2-year Lockwood electromechanical warranty. View CTX-SSPLT-3772
• ADICTXSPSSS — ADI branded, suits Lockwood Cortex 530 series. 230 x 75 x 1.6 mm satin stainless, sold as a pair. View ADICTXSPSSS

ASSA ABLOY Aperio Scar Plate

The E100-PL2SSS is the scar plate for the Aperio E100 electronic escutcheon — a commercial access control product common in apartments and offices. 52 mm diameter, 1.2 mm satin stainless, sold as a pair. View E100-PL2SSS

Gates and Aluminium Doors

What the Gate Images Show

Two of the installation images in this blog show Borg mechanical-digital locks on aluminium gates — a decorative laser-cut gate and a louvred slat gate. Both show a small scar plate above the lock body at the gate rail. On aluminium gates, scar plates serve a slightly different purpose than on timber doors.

Aluminium gate rails — particularly the hollow-section extrusions used in laser-cut and slat-style gates — often need to be drilled or notched to accept the lock body. The resulting hole is visible above and below the escutcheon, and a scar plate covers it cleanly. Unlike timber, aluminium doesn't fill or compress under drilling — any misalignment or overdrilling is permanent and fully visible without a cover plate.

Material Choice for Gates

For gate applications, 304 grade stainless steel is almost always correct — gates are typically in exposed exterior positions in Queensland's coastal environment. The McGrath aluminium plate (MLSPWINSPALU) is an exception designed for aluminium door frames; for gates, stainless is the default.

Borg BL2000KSC on a louvred slat gate. The narrow scar plate at the top of the lock covers the cut-out where the rail was notched for the lock body.

Thin-wall aluminium caution: Gate rails often have 1.5 mm to 2 mm aluminium wall thickness in hollow-section extrusions. Scar plate fixing screws must be selected and torqued carefully. Over-tightening will strip the thread or deform the material. For gate installations, consider having Terry's do the job — see the installation services page for what's covered.

Frequently Asked Questions

Common Questions

Do I need a scar plate for every smart lock installation?
No. Scar plates are only needed when the new lock's escutcheon doesn't fully cover existing holes or damage on the door face. On a new door with no prior hardware, they're usually not required. On a retrofit or upgrade, check both sides before deciding.

Can I use a generic scar plate rather than the brand-specific one?
Sometimes, but with caution. A generic plate works where you only need cosmetic coverage and there's no internal cut-out requirement. Where the lock body needs to pass through the plate (Lockton Elev36), a generic plate won't work. On fire doors, only tested plates on the approved hardware log are acceptable.

Are scar plates sold as a pair or individually?
Most smart lock scar plates are sold as a pack of two — one per door face. The Lockton PS-REC-36 series is the exception, sold as a single plate. Check the product page before ordering.

My new lock doesn't fully cover the old holes. Do I need to fill them first?
Not necessarily. A correctly sized scar plate covers the holes without filling them. If the holes are deep enough to cause structural concerns in a thin-wall gate rail, talk to Terry's before ordering.

The previous lock left surface scratches, not holes. Will a scar plate help?
Yes. Scar plates cover surface damage as well as holes. Any marks within the plate's footprint will be concealed once the plate is fitted and the escutcheon mounted over it.

Can the wrong scar plate affect door alignment or lock function?
It can. A plate with an incorrect cut-out means the lock won't seat correctly, putting stress on the spindle and affecting locking performance. Always use the plate designed for the specific lock. See the common DIY installation mistakes guide for more.

Where can I browse all scar plates Terry's stocks?
The full range is at goldcoastsmartlocks.com.au/smart-lock-accessories/scar-adaptor-plates-for-smart-locks/.

Related Guides

Not Sure Which Scar Plate You Need?

Tell Terry's what lock you're fitting and what the door looks like — they'll tell you exactly which plate to use, or whether you need one at all.