Continuous Bend: One-Piece Steel Door & Window Frames

Formed from a single, unbroken length of steel.

Forming a steel window or door frame has traditionally meant working in pieces. Continuous Bend Technology changes that.

To build up a full steel frame profile, fabricators have traditionally cut steel into sections and joined them, often adding extra layers of metal to achieve the depth and shape the frame required. Every cut and added layer introduces a seam: a place where the frame relies on a weld for continuity, where a line can show, or where finishing becomes harder.

Continuous Bend Technology removes those seams. The frame is formed from a single piece of steel, bent in one continuous pass, so the section runs uninterrupted from corner to corner. The only joints are two welds at the base of the frame.

PINKYS forms the frame on a CNC profile bending machine: a hydraulically controlled machine fitted with custom rolling dies and tooling blocks shaped to the specific profile being bent. One length of steel is bent in a continuous motion into the full frame profile. Because each profile has its own geometry, the tooling is matched to the specific system. When the bend is complete, the frame is closed with just two welds at the bottom.

handmade steel window history
three steel arch top doors made with continuous bend technology

Steel types formed by Continuous Bend

SystemSteel TypeWall Thickness
Ottostumm FerroFinestra W20Solid hot-rolled steel3-5 mm
Ottostumm FerroFinestra W40Solid hot-rolled steel3-5 mm
Ottostumm W50 TBCold-formed tubular steel with integrated polyurethane thermal break1.5-1.8 mm

W20 and W40 use thick, solid hot-rolled steel to achieve structural rigidity with a slim sightline. W50 TB is a hollow, cold-formed tubular profile with an integrated polyurethane thermal break; its lighter wall thickness relies on the tube's box geometry, rather than solid mass, for structural strength. Continuous Bend Technology forms all three profiles from a single, unbroken length of steel.

Because the section is continuous and the joints are reduced to two welds at the base, a continuous-bend frame differs from a conventional one in ways architects will notice:

  • Continuity from corner to corner. The frame is a single, uninterrupted member rather than several pieces relying on joints.
  • A cleaner appearance. Fewer welds and joints mean fewer visible lines in the frame; the two welds that remain sit at the base, away from primary sightlines.
  • A leaner section. Eliminating the extra layers of steel previously needed to build up the profile removes built-up bulk.
  • Simpler finishing. Fewer seams and crevices mean fewer places where finishing and long-term protection are challenged.

Frequently Asked Questions

Continuous Bend Technology is a process PINKYS uses to form a steel fenestration frame from a single piece of steel, bent in one continuous pass on one machine. The full frame is one piece of metal with only two welds at its base — no cuts, no breaks, and no added layers of steel.
Two, both at the base of the frame. The rest of the frame is a single, continuous piece of steel with no breaks.
A conventional frame is cut into sections, joined, and often built up with extra layers of metal. A continuous-bend frame is formed from one piece in a single bend, so the section is continuous with only two welds at the base.
Yes. With fewer joints and welds — and the two remaining welds positioned at the base — the frame reads cleaner, with fewer visible lines.
Yes. Continuous Bend Technology is used across PINKYS's Ottostumm-built Studio Steel systems, including the W20, W40, and W50 TB profiles, for both exterior and interior steel doors and steel windows.
closeup of continuous bend arch top steel door
steel windows and doors historic maker

Specify W20 for Your Project

Share the opening dimensions, configuration, and glazing requirements. PINKYS produces architecturally detailed CAD drawings and works through the specification one on one. The PINKYS Studio Steel team handles the rest.

Book a Consultation
Live Chat
Need help? Ready to buy?
Chat with a PINKYS specialist now!
Call Us 1-844-843-6677
Mon - Fri: 8 AM - 5 PM
Sat: 11 AM - 2 PM
Email Us
Need more info or got a question?
Send us a message!