A Guide to the Parts of a Door

A door can look simple from the outside, but there’s a lot going on beneath the surface. From the slab you see every day to the hidden reinforcement, locks, hinges, and frame, the parts of a door all play a role in how it feels, how it performs, and - most importantly - how well it protects your home.

Below, we’ll break down the basic door parts you’ll find in most high-quality external doors, then go deeper into door handle parts, door lock parts, and door frame parts - and finally, what makes Stronghold’s approach different.

Basic Parts of a Door

Most people think of a door as just the panel and the handle. In reality, the core structure (and how it all fits together) is what determines strength, stability, and longevity.

Here are the key door parts you’ll typically find on a front door or high-security external door:

• Door leaf (the slab/panel): The main body of the door. This is the part you open and close.
  
  
• Door core: The internal “skeleton” that gives the leaf its rigidity. In a security door, this structure is formed from reinforced components and includes a full-size steel sheet running across the entire door leaf. This is where serious strength is built in - such as a multi-layer reinforced steel core with a custom thickness depending on specification.
  
  
• Face materials/skins: The visible surfaces (for example, timber, metal, or bespoke finishes).
  
  
• Hinges: The mechanical joints that carry the weight of the door. Stronghold uses bespoke-made hinges, including concealed hinge options.
  
  
• Seals and thresholds (where applicable): Help with draught control, weather resistance, and day-to-day comfort.
  
  
• The door frame: The fixed structure anchored to the wall that the door locks into (more on this below).

When you’re comparing door and lock parts between a standard door and a true security door, the biggest differences are often the ones you can’t immediately see: reinforced cores, anti-cut and anti-drill layers, and engineered frames designed to resist attack - not just look good.

Door Handle Parts

Your handle isn’t just a “grab point” - it’s part of how the door is operated, latched, and secured. Depending on the door setup, door handle parts may include:

• Lever or pull handle: The part you hold to open the door.
  
  
• Backplate or rose: The plate the handle mounts to (often hides fixings for a cleaner look).
  
  
• Spindle: A metal bar that runs through the door, connecting the outer and inner handles so that they turn together.
  
  
• Spring cassette (in many modern handles): Helps the handle return smoothly.
  
  
• Fixings and through-bolts: Proper fasteners matter - especially on heavier doors where movement and load are greater.

On higher-end security doors, handles can be chosen to suit the look of the home (modern, heritage, minimalist), without compromising the engineering behind the scenes. Stronghold supports heritage detailing and luxury finishes - like metal inlays, hand-finished timber, and powder-coat custom colours - so that you’re not forced to pick between “secure” and “beautiful”.

Door Lock Parts

If you’ve ever searched for door lock parts, you’ll know there’s more than just a keyhole. And in security doors, the lock isn’t one component - it’s a system.

Here are common door lock parts you may find in a high-security setup:

• Cylinder (the part the key enters): Many premium doors use a high-security cylinder designed to resist drilling and picking. Stronghold specifies an anti-drill, anti-pick cylinder option with a cylinder defender to further boost security.
  
  
• Lock case (mortice): The main lock body inside the door.
  
  
• Latch: Holds the door shut when closed, even without turning the key.
  
  
• Deadbolt: A solid bolt that extends into the frame when locked.
  
  
• Keep/strike plate: The reinforced metal plate in the frame that receives the latch/bolt.

Multi-point locking (and why it matters)

Single-point locks concentrate strength in one area. Multi-point systems distribute it across the height (and sometimes width) of the door. Stronghold doors use a multi-point locking system with a custom locking spread, including 4 directional locking, built around proven Iseo 600 series and Mottura armoured lock mechanisms.

You can also add shootbolts (additional locking bolts), either operated by the same key or a separate key, depending on your preference and how you want the door to function day-to-day.

Smart and keyless options

Security and convenience don’t have to be opposites. Stronghold offers motorised smart locking compatible with home automation, plus optional biometric lock integration (fingerprint, facial recognition, card) and RFID/touch-to-open access systems.

These features don’t replace robust physical security - they build on it, giving you modern access control on top of hardened door and lock parts.

Door Frame Parts

The door leaf can be incredibly strong, but if the frame is weak, the whole system suffers. That’s why door frame parts matter just as much as the lock.

Key frame components include:

• Head (top of the frame)
• Jambs (the vertical sides)
• Threshold or sill (bottom section, if used)
• Fixings/anchors into the surrounding wall
• Reinforcement and protection plates around lock points (especially on security doors)

Stronghold uses an armoured steel door frame, designed to stand up to the same kind of attack resistance as the leaf itself. They also offer a concealed steel frame reinforcement system - hidden strength with a cleaner, more aesthetic exterior.

In other words, the frame isn’t an afterthought. It’s an engineered partner to the leaf, locks, and hinges - so the whole doorway performs as a single protective unit.

What Sets Stronghold Apart

A lot of brands can list door parts and hardware. The difference is how those components are built, integrated, and tailored to the risk level and the property.

Stronghold’s security doors can include:

• Multi-layer reinforced steel cores, with custom thickness depending on specification
• Ballistic-rated core options for higher-threat environments
• Anti-cut / anti-drill reinforcement designed to resist targeted attack methods
• An armoured steel door frame and concealed reinforcement, so that the strength isn’t always visible from the street
• A hardened locking solution with an anti-drill, anti-pick cylinder and a multi-point locking system with 4 directional locking
• Optional upgrades like shootbolts, smart locking, and biometric/RFID access
• Bespoke-made components such as hinges (including concealed hinges) and a secret chain
• A finish-first mindset: heritage detailing, premium materials, and custom colour options

A Quick Way to Think About It

If you’re assessing parts of a door for security, don’t just ask, “What lock is on it?” Look at the full system: what’s inside the leaf, how the frame is reinforced, how many points the door locks into (and in which directions), and whether the locks and hardware were engineered to work together from day one. 

That’s where the real difference shows up - not in one impressive component, but in a complete setup that’s built to protect, built to last, and still built to suit your home. If you’re considering a new security door (or upgrading what you have), contact Stronghold to talk through your requirements and get a specification that matches your property, risks, and preferred finish.