Where a steel door actually begins
Buyers usually judge a steel door by its face. Inside the workshop, the face is the last thing anyone worries about. The sequence is sheet, cut, brake, weld, fill, press, finish, hardware — and a millimetre lost early shows up at the end, when the leaf refuses to sit in the frame.
Leaf skins are commonly formed from cold-rolled steel sheet in the 0.8–1.2 mm range. Frame profiles use thicker material, because the frame carries both the weight of the leaf and any impact from outside. Thickness alone is a poor quality test: a well-braked thin profile can be stiffer than a badly braked thick one. Below 0.8 mm on the visible skin, though, the first hard knock leaves a dent you cannot press out.
Cutting and forming
Plain-faced doors are cut on CNC guillotine shears. Patterned doors go to the laser, where the motif, the glazing apertures and the handle and viewer holes are cut in one program so the pattern stays symmetrical about the leaf centreline. For custom laser cut steel doors, rescaling a motif to a non-standard width is a fresh programming job rather than a copy of the previous file — worth knowing when you ask about lead times on a bespoke order.
Press braking follows. The folds around the leaf give it edge stiffness; the folds in the frame profile form the legs that meet the wall and the shadow gap the leaf closes into. The frame is welded from four pieces and squared after welding. A corner out of square by a millimetre or two will rub on one side and show daylight on the other, and no amount of adjustment at installation fixes it.
Core, hardware and finish
The cavity between the two skins decides how the door sounds, weighs and insulates. Polyurethane foam fills the void completely and helps the leaf behave as one piece. Mineral wool is chosen where fire resistance and acoustic performance matter. Honeycomb board is the cheap option and announces itself with a drum-like knock. Whatever is used, it has to be bonded to the internal frame, or it settles and leaves a hollow at the bottom of the leaf.
Surface work is both appearance and corrosion protection. Vacuum-pressed PVC membrane follows the depth of laser-cut relief, which is why it dominates patterned ranges. Laminate and ultralam steel doors give a harder surface with better scratch resistance. Powder coating suits single-colour and matt specifications. For containers heading to hot or humid climates, ask specifically how the chosen surface behaves under UV and moisture, not just what it looks like.
Locks, cylinders, escutcheons, handles and hinges go on once the leaf is complete. The number of bolts and how deep they travel into the frame matter more than the badge on the cylinder. Security pins on the hinge side keep the leaf attached to the frame even if the hinges are attacked.
Sizes, inspection and export
Standard apartment doors are built around a 90 × 200 cm clear frame opening, finishing at roughly 108 × 210 cm over the architrave. Building entrance and villa doors work from 145 × 215 cm clear, finishing near 165 × 223 cm, with frame depth adjustable between 20 and 24 cm for thicker walls. Anything outside these figures is a made-to-measure order: the pattern is rescaled, the frame recut, the lock axis repositioned.
Before packing, every leaf is hung in its own frame and tested. The perimeter gap must be even at 3–4 mm, the bolts must travel without forcing, the key must turn with one hand, and the gasket must run unbroken around the leaf. Doors are then crated with frame, hardware and fixings as a matched set, numbered so the site crew pairs the right leaf with the right frame.
We ship from Istanbul, and for container orders the practical questions are quantity per size, surface finish, lock specification and the wall thickness at destination. Send your opening sizes in centimetres with the model you like and we will quote per door and per container.
