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D-Shaped Tube

D-shaped tube, or D tube, has a distinctive ridged design which boasts tremendous lateral strength. It is easy to grip, and has a flat, secure base which is easy to apply to bulwarks, brickwork and balustrades – including glass.

D-Shaped stainless steel tubing being used a balustrade handrail
  • Developed with ease of installation in mind
  • Technically and aesthetically superior to standard round tube
  • Often used as handrail due to its ergonomic design
  • Distinctive ridge creates a flat and secure base to apply to bulwarks, brickwork and balustrades
  • Tremendous strength (49% stronger than standard round tube equivalent in robust deflection testing)
  • Rainwater flows off the curved top, preventing unwanted water ingress
  • Joiners available for some D-shaped tube sizes, enabling easier fabrication for handrails and balustrades

6 existing sizes of stainless steel D-shaped tubed multiple wall thicknesses

From 34×12×1.5mm to 178×58×3mm

Most popular sizes

  • 34 × 12 × 1.5mm
  • 50 × 18 × 1.5mm
  • 65 × 28 × 2mm
  • 99 × 40 × 2mm
Mutliple sizes of D-Shaped stainless steel tubing in a mirror finish

Designed for handrail use

D-shaped tube is predominantly used as handrail – the profile was ergonomically designed to be gripped by a hand. Its flat underside helps fabricators and fitters to weld square-cut balusters directly to the underside of the tubing. It is also possible to attach a glazing channel to the D-shaped handrail either through welding or by attaching threaded inserts to the underside.

Find out more about our unique Handrail
D-Shaped metal tubing balustrade with twisted oval tubing spindles
A glass balustrade with a stainless steel D-shaped rail overlooking Sandbank, Dorset, UK
Glass balustrade with stainless steel D-shaped Handrail.

Easy maintenance

The unique shape not only aids installation but it will also stop water ingress to the underside. This makes it more corrosion-resistant, as it reduces pitting and water collecting underneath. This makes D-shaped tube ideal for when used as external handrails for ramps and stairs and balustrades in public buildings, as well as yachts and cruise liners.

A great alternative to teak wood railings on boats

For centuries, teak wood has been used aboard sea-faring craft, but teak is becoming increasingly limited in availability and increasing expensive. When made from ‘marine grade’ 316L stainless steel, the D-shaped profile makes a wonderful alternative to teak bulwark capping on larger boats and cruise liners. It has become the selection of choice for boat owners and shipbuilders alike since it requires no maintenance and will always look new. However, if a traditional teak wood-effect is desired, we can apply a special coating to the metal (this can be applied to aluminium and stainless steel tubing).

Discover more about our marine railings
D-shaped stainless steel tubing with a powder-coated wood effect finish
Stainless steel D-shaped tubing being used to house electronic components for a seismic measuring device

D-tube for engineering projects

Product designers and engineers have found that this geometric tube profile is an especially useful solution to house electronic components and cables. We can custom-make this tube in various sizes (we make D-shape tube in a super-slim profile to be used to house a geotechnical sensor, for example). If you are looking to experiment with tube shapes and sizes, speak to us about our prototypes and customised sizes.

Metals available for the D-shaped profile

Most often, we make the D-shaped tube profile from stainless steel (inox) and aluminium due to the applications that it is used for, although it can be made from brass, copper and cupronickel.

Find out more about our Metals and finishes
stainless steel in a mill finish
Stainless Steel
aluminium in a mill finish
brass in a mill finish
cupronickel in a mill finish

Joiners available for connecting D-shaped tube

We offer a joining system for some of our most popular-sized D-shaped tubes. The stainless steel joiners enable you to produce handrail and balustrades with uncompromising, seamless joins. If we don’t yet make joiners in the size you require, speak to the team as we can custom-make sizes.

View Joiners
D-shaped hand rail tubing joiner
Timeless engineer welding machined components onto a length of D-shaped stainless steel tubing

Fabrication service for D-shaped tube

If your application requires the D-shaped tube to be cut, welded and polished then ask about our in-house fabrication services. Our expert fabricators are highly experienced in preparing D-shaped railings so that they are ready for installation.

Should you require, our fabricators can channel-cut the D-shape tubing to create a glazing channel that holds a glass panel (or alternatively we can weld clamps and fittings to secure glass panelling). We can also weld our stainless steel spindles or posts to the D-shaped handrail tubing.

Read more about our expert metal fabrication


Stainless steel and aluminium 5083 D-shaped tube profiles are sold in lengths of 5.8m (the manufacturing process reduces the standard 6m length by 0.2 metres).

Can’t see the tube sizes you need in the table? Contact us about custom-sized tubing; we may able to fabricate a new size to meet your project requirements. Or download our brochure, which contains sizing information for existing aluminium and brass tubing too, as well as all stainless steel sizes.


If required, we can find out wall thickness tolerances from our metal suppliers. Typically the tolerance levels of wall thickness are extremely minimal and any small variations in thickness do not affect further fabrication or the end application. However, it is important to tell us if the tolerance is critical to the application before you place an order. For example, if the shaped tubing component needs to go inside another component, or if the tubing has to house a component, any variation in wall thickness could be critical.

The image above shows how dimensions are detailed
(for example, 34mm x 12mm x 1.5mm)

Sizes given below are for stainless steel.

Tube Sizes
34mm x 12mm
50mm x 18mm
65mm x 28mm
99mm x 40mm
138mm x 49mm
178mm x 58mm
wall thickness
wall thickness
wall thickness
Scroll to view Sizes
Show Imperial Sizes
Download Size Chart PDF

Applications for D-shaped Tube

  • Railings
  • Balustrades
  • Guardrails
  • Kick rails
  • Banisters
  • Balconies
  • Metal Stair Nosing
  • Housing for electronic components

International shipping for D-shaped tube: efficient overseas shipping options

Our clients come to us from across the globe for our unique shaped tubing and specialist tube fabrication. We can ship D-shaped tube to North America and Europe in as little as 48 hours. Our expert shipping team will meet your transit times and budget; get in touch to discuss transportation options.

Find out more about international shipping
International shipping
Timeless specialists looking over technical drawings for a tubing project

Need help finding the right size and tube shape?

Speak with one of our tube specialists to find out how best to integrate shaped tubing into your project. We can give you information on the best profile, metal, finish and dimensions for your application.

Talk to a specialist

Contact us for expert advice, quotes and free samples.


We can develop new sizes

Don't see a size you need? Just specify the size you require in your message.

We can develop new sizes

Don't see a size you need? Just specify the size you require in your message.

We can develop new sizes

Don't see a size you need? Just specify the size you require in your message.

We can develop new sizes

Don't see a size you need? Just specify the size you require in your message.

We can develop new sizes

Don't see a size you need? Just specify the size you require in your message.

We can develop new sizes

Don't see a size you need? Just specify the size you require in your message.

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