Precision tubing for lamp arms, threads, connectors and chrome-plated lamp holders
The technical challenge of lighting
The finish is the product
In a design lamp, the steel tubing is the most visible element: the articulated arm, the base column, the neck of the desk lamp. There is no housing to cover it. Chrome plating with the porosity of the steel showing through, a rolling mark, a haze after the plating bath: that is not a minor defect, it is a reject. And in lighting, the reject is visible from a metre away, switched on.
The thread has to engage first time
A lamp is also an assembly of parts: the tubing screws into the lamp holder, the connector, the base. If the diameter is not calibrated or the internal weld bead invades the thread, the part does not fit or sits loose. On an assembly line producing thousands of luminaires, every thread that does not engage first time is lost time.
The shape is part of the design
Decorative lighting rarely settles for plain round tubing. It calls for square and oval sections, barley-twist profiles, knurled textures. The tubing has to arrive with that shape already resolved, without compromising the bright finish.
Applications where you will find us
Lamp arms and columns
- Bright surface ready for the plating bath The PREMIUM range leaves the factory with a bright, non-porous outer surface: from the warehouse to the chrome, nickel or lacquer bath with no prior polishing stage. The processor eliminates a whole process and the visual rejects that come with it.
- Bending without compromising the finish Thin walls with the formability needed for articulated arms and tight bends, without cracking or ovalisation, keeping the surface intact.
- Non-circular and decorative profiles Square, oval or flat oval section to EN 10305-5; barley-twist (torsioned) profiles and knurled textures incorporated into the manufacturing process itself.
Threads and connectors
- Diameter calibrated to a hundredth of a millimetre So that the thread engages first time and the connector fits with exactly the clearance specified in the drawing.
- Controlled internal weld bead The OPTIM range keeps the internal weld bead at ≤ 0.15 mm: the thread and the internal wiring are left clear, with no bead invading the bore.
- Tubing with an integrated thread When the customer needs it, we deliver the tubing already threaded, not just cut: one less part to machine at their plant.
Lamp holders and chrome-plated small tubes
- Direct chrome, nickel, zinc and brass plating The tubing behaves consistently across all treatments, so a single family of luminaires can vary its finish without changing base material.
- Very small diameters Below 8 mm, where the market for calibrated tubing all but disappears, sits much of the lighting component: lamp holders, small tubes, fine connectors.
- Screen printing and decorative finishes When the part needs branding, a reference or a visible distinguishing finish.
The right range for iluminación
PREMIUMArms, columns, necks and all exposed tubing. Bright outer surface for direct chrome, nickel or lacquer plating, with no prior polishing
OPTIMThreads, connectors and precision joints where the bore matters. Internal weld bead ≤ 0.15 mm
PRECISELarger-diameter columns and necks that demand a finished bore. Mirror bore
Not just the tubing: the finished part
- From the warehouse to the chrome bath,From the warehouse to the chrome bath, with no step in between. It is the central argument for the PREMIUM range in lighting: the as-supplied bright surface eliminates the polishing stage before electroplating, along with its cost, its time and its risk of batch-to-batch inconsistency.
- Tubing transformed into a component ready to assembleWhen the customer needs it, we do not deliver tubing: we deliver the finished part. Cutting, bending, punching, end forming, threading and surface finishing —to drawing— so that the lamp arm arrives ready for the plating bath and from there to assembly. One manufacturer instead of four suppliers.
- Coil format or cut-to-length, to elimiCoil format or cut-to-length, to eliminate end-of-bar scrap on luminaire manufacturers' automated lines.
Why lighting manufacturers trust Delmàs
A family-owned business in La Roca del Vallès, specialising exclusively in small-diameter welded and calibrated steel tubing (⌀ 3–25 mm).
The bright surface of the PREMIUM range goes straight to the plating bath: zero visual rejects from imperfections in the base tubing, zero cost of prior polishing.
Below 8 mm —the territory of lamp holders, connectors and small lighting tubes— the supply of precision calibrated tubing all but disappears. That is where we have been working for decades.
Manufacturing powered 100% by renewable energy since 2006, with two photovoltaic self-consumption installations at the plant.
Questions we hear every week
Does the tubing arrive ready for chrome plating?
Yes. The PREMIUM range is manufactured with a bright, non-porous outer surface, suitable for direct chrome, nickel, zinc or lacquer plating, with no prior polishing stage. It goes from the warehouse to the plating bath with no step in between.
Do you manufacture tubing with a thread for a lamp holder?
Yes. As well as calibrating the diameter to a hundredth of a millimetre so the thread engages first time, we can deliver the tubing already threaded as a finished part, to your drawing.
Can you manufacture square, oval or decoratively shaped tubing?
Yes. We manufacture non-circular profiles to EN 10305-5 —square, oval, flat oval— and decorative profiles such as barley-twist (torsioned) or knurled textures, incorporated during manufacture and keeping the bright finish.
Do you manufacture the fine tubes for lamp holders and vintage bulbs?
Yes, that is our speciality. We work small diameters, below 8 mm, where most tubing manufacturers cannot reach.
Do you deliver the finished lamp arm or just the tubing?
Both. As well as tubing in coil or cut to length, we transform the tubing into a finished component ready to assemble: cut, bent, punched, threaded and with the surface ready for the plating bath.