A slamlock security gate locks itself the moment you pull it shut: a spring-loaded bolt snaps into the frame, and you only need a key to open it again. That is why they are so common on kitchen and back doors where hands are full. Share the opening size and how you use the door, and gate manufacturers and installers near you send quotes straight to you at no cost.
How a slam lock works
Inside the lock box is a sprung latch bolt with an angled face. When the gate swings shut, the angled face pushes the bolt back, and then the spring throws it into a keeper on the frame. A deadbolt sits behind it; turning the key throws that bolt as well for extra holding force. Pull the gate closed and it is latched, though not yet deadlocked, which is why you should turn the key at night.
Cheaper latches wear in a few years and begin to rattle, whereas a boxed lock with a hardened bolt keeps its fit for a decade or more.
Some designs hold the gate open with a hook or stay so the latch does not catch your fingers or the wind.
Keys, cylinders and key control
Budget lock boxes take a flat key with few levers and can be matched by any hardware store key cutter. Better boxes use a cylinder with a restricted key profile, which is copied only on proof of ownership. Ask for the same key on every gate, kitchen and patio, or keyed alike. A key needed on both sides is stronger, but it is a hazard in a fire, so store a spare on a hook near the door, out of arm's reach through the bars. See security door locks for the full range.
Steel, hinges and fitting
The lock is only as good as the frame it bolts to. A slamlock gate should have 25 x 25 mm tube or heavier, bars at least 12 mm thick, a mid-rail, and welded hinges set at the top, middle and bottom. The keeper must be bolted to the frame with long anchors set into brick or concrete, not into a soft plastered corner. Poor fixing is the most common failure, so mention hollow brick or old plaster when you request quotes. Ask for a photo of the finished keeper fixing if you cannot be there.
Everyday problems
A slam gate that will not latch usually means the gate has dropped on its hinges and the bolt no longer lines up. Sticking keys are normally dirt or rust in the cylinder, solved with graphite powder rather than oil. Ask the installer to adjust, not replace, before paying for a new gate. Salt air and kitchen steam also corrode lock boxes, so a stainless or galvanised box is worth the small extra cost near the coast. For heavier jobs see security gate repairs.
What to include in your request
- Opening width and height in mm
- Round or square bars and the gap you prefer
- Keyed alike across several gates
- Whether you need an inside thumb-turn
- Wall type for the lock keeper fixing
Slamlock Security Gates for different properties
- Houses: a slamlock gate on the kitchen and back doors so it latches when your hands are full
- Townhouses and complexes: a gate on the patio door, often in black or white to meet the rules
- Flats and apartments: a slim slamlock gate on the front door with an inside release
- Farms and smallholdings: strong keyed-alike gates for the house, dairy and tool rooms
- Shops and restaurants: a latching gate on the staff entrance and delivery door
- Offices and practices: a gate on the server room or archive, using restricted keys
- Factories and warehouses: heavy slamlock gates on stores and compounds, built from thick tube
- Schools, clinics and churches: slamlock gates on stores, with inside release to meet escape rules
Frequently asked questions
What does a slamlock security gate cost?
Can I get a slam lock that opens from the inside without a key?
Can I change the lock on an existing gate?
Why does my gate lock itself with the key inside?
Slamlock Security Gates by province and city
- Johannesburg
- Pretoria
- Centurion
- Midrand
- Sandton
- Randburg
- Roodepoort
- Krugersdorp
- Randfontein
- Germiston
- Boksburg
- Benoni
- Kempton Park
- Alberton
- Vanderbijlpark
- Vereeniging
- Durban
- Pinetown
- Pietermaritzburg
- Richards Bay
- Newcastle
- Ladysmith
- Gqeberha (Port Elizabeth)
- East London
- Kariega (Uitenhage)
- Mthatha
- Cape Town
- Bellville
- Paarl
- Stellenbosch
- George
- Worcester
- eMalahleni (Witbank)
- Middelburg
- Secunda
- Mbombela (Nelspruit)
- Rustenburg
- Brits
- Klerksdorp
- Potchefstroom
- Mahikeng
- Polokwane
- Tzaneen
- Kimberley
- Upington
- Bloemfontein
- Welkom
- Sasolburg