When you restore a protected historic building, you don’t design the windows from scratch, but you rebuild them. Every window is a one-off that has to fit the original design, and the risk of falling back on manual work is always there.

Stuyts faced this challenge when it made new wood windows for the former Halenstraat fire station in Antwerp (Belgium) on a Weinig Vario MC 50 machining center. This article tells you how it went.

The Halenstraat building was designed by architect Emiel Van Averbeke. Construction started in 1911 and finished in 1913. The building served as a fire station until 1947 and was later turned into social housing. Today it is a protected historic landmark, so any work on it must keep its historic character intact.

The façade still has its original look. Above the two large entrance arches, where the fire trucks once drove out, the word Brandweer is carved in stone. It means “fire department” in Dutch. On the ground floor, the main doors are large round-arched wood frames divided into panels. On the upper floors, the windows sit between the small stone columns that decorate the facade. The tower has a large arched window.

The new wood windows and doors were built by Stuyts, a Belgian woodworking company founded in 1892. It is based in Zoersel, a few miles from Antwerp. The company works in two areas:

• custom interiors, such as kitchens and bookcases;
• windows, doors and exterior work: wood windows, entry doors, façade cladding and gates.

Stuyts has combined traditional craftsmanship and new technology for more than a century, so the Halenstraat fire station was a natural test. The job was to reproduce early-1900s shapes with a modern production process.

A rectangular window follows rules you can repeat. Stiles and rails meet at 90°, the profiles are straight, and you set up the joints once. In the windows of the former fire station, almost none of these rules apply.

Making these windows involved three kinds of complexity:

• the arches are made of several segments, joined along the curve. An arch this large can’t be cut from a single piece of wood;
• rails and stiles meet the arch at a different angle at every contact point;
• the frames have angled or curved sides, which create trapezoid-shaped or wedge-shaped panels.

For the Engineering team, this means every part has its own shape. The profiling has to follow the curve, the joints have to fit at non-standard angles, and the joint holes have to line up between curved and straight parts. A mistake on one arch segment often shows up only at assembly, when the frame won’t close.

That’s why a powerful machine and good software aren’t enough to automate work at this level. You need a programming strategy in place before you create the first program:

• how to split the arch into segments;
• in what order to machine the parts;
• how to clamp them on the table;
• which tools to use for profiling along the curve.

Stuyts made the parts on a Weinig Vario MC 50, a compact machining center built for solid wood windows and doors.

Three features of this CNC machine matter in a project this demanding:

• 5-axis technology: the tool can tilt in relation to the part, which is essential for profiling along an arch and machining joints that aren’t at right angles;
• many options for corner joints: this is what you need when rails and stiles meet the arch at a different angle at each joint;
• PowerGrip Motion clamping: it combines single clamps with a continuous clamping bridge. With slot clamping, the clamps can be positioned in 2D, and with the extra Z axis also in 3D. This gives stable grip points even for curved segments and irregular parts.

Weinig also lists full round arches among the machine’s applications. But having the right machine is only the starting point. The project went beyond installing software: it took specialist skills, experience and ongoing support.

EPW (Efficient Processing Wood), the DDX representative for Belgium and the Netherlands, followed the project closely and developed the programming strategy for the most complex parts. In practice, EPW connected two worlds: the craftsmanship of Stuyts on one side, and on the other the logic of the CNC machine, a tool that needs exact shapes, sequences and settings.

This step is often underestimated. With custom windows, whether a part comes off the machine ready to use or needs hand finishing depends mostly on the strategy, not on the power of the machine.

Do you work in Belgium or the Netherlands? Your local DDX partner is EPW.

The DDX software used in the project is PowerWIN, a CAD/CAM software for designing and making windows and doors.

With PowerWIN, you can:

• create a project from a new model with custom settings, or import a drawing in a supported format, including custom windows that aren’t in the catalog;
• create machine programs that handle angles that change from one joint to the next on curved and angled frames;
• preview the machining in a 3D model of the machining center;
• check for collisions between tools, machine parts and workpieces before the program goes to production;
• automatically generate ISO code to machine one or more parts on 3-, 4- and 5-axis machines.

The result: the craftsmanship that historic windows require became an automated, reliable production process. The curved and angled parts come off the machine, get assembled on sawhorses in the shop and, after finishing, go to the job site ready to be installed in the Halenstraat arches.

Stuyts, EPW and PowerWIN show that historic craftsmanship, CNC technology and know-how can work together, even on arches and angles that once seemed to require hand work. With the right strategy, a Weinig Vario MC 50 can automate production even for the windows of a protected 1913 building.

Do you make custom windows and doors and want to move them to your CNC machining center?