How are curved handrails made

Those stunning, curved bespoke handrails you see in homes you visit and on Pinterest don’t grow on trees, you know. It takes a great deal of time and effort to bring these gorgeous creations to life, but how is it actually done? Well, there’s a few methods to choose from…

CNC machining

This is the method we use here at Handrail Creations, as it allows for greater accuracy, and ensures the process runs quickly and smoothly. CNC (Computer Numerical Control) machines use computer software that controls tools – such as lathes or routers – to create very precise and complex shapes with a high level of accuracy and efficiency.

The handrail’s shape is designed using CAD (computer-aided design) software, which can be used to create complex 3D models. Once complete, the design is converted into a CAM (computer-aided manufacturing) program, which tells the CNC machine the specific movements and cutting paths required to create the handrail.   

Next, the chosen timber is prepared for machining which may involve it being cut to size, clamped securely, or mounted on a rotary axis for more complex curves. The CNC machine follows the instructions given by the CAM program to cut the handrail. The cutting tool, often a router or lathe bit, is precisely controlled to create the desired shape and profile.

After machining, the handrail may require additional finishing such as sanding, staining, or painting.

There are a number of advantages that CNC machines offer compared to alternative methods, including its high degree of accuracy, their efficiency – which reduces labour costs and boosts production speed, and the fact that they can handle complex and highly customised projects with ease.

Steam bending

This traditional method involves exposing the timber to steam in order to make it more pliable. The heat and moisture generated from the steam works to gradually soften the fibres of the wood so it can be bent while warm, and retain that new shape once it has cooled. 

The steaming is done by placing the timber in a steam box for a certain amount of time, depending on the type of wood being used and its thickness. Once the timber has been steamed for the correct amount of time, it gets pulled around a jig or former as quickly as possible while the heat is retained. The bending timber can be reinforced with a metal band to help support the timber as it is strained due to the tension and compression of the process – this can help minimise the problem of splits. Once the timber has been bent into the desired shape, it is clamped and left to cool and dry.

This method is primarily used for hardwoods such as maple, mahogany, and oak, although a straight grain timber is recommended – along with avoiding knots! It is mostly suited for constructing large radius curves.

Of course, there are certain disadvantages to steam bending. It’s a highly time-consuming process, as it not only involves steaming and bending, but also drying the wood, which can take a lot longer for larger or intricate designs. It’s also not suitable for all types of wood, as some are more prone to cracking or splitting than others, and if not done correctly the wood’s fibres can become damaged, leading to weakened areas or even fractures. There are also environmental concerns, with the use of water and steam having an impact on energy consumption and water usage. Steam bending is only typically used when a groove is not required, and it’s also not a suitable technique for ‘ramps’, ‘corners’ and ‘scrolls’. 

Laminating

Laminating is a process where multiple thin layers of timber are glued together to form a composite. These layers can be shaped or curved individually and then bonded together.

For curved wooden handrails, individual layers are prepared for bonding by cutting them to size, shaping them as per the design, and applying the adhesive. These prepared layers are then arranged in a stack; the direction of the grain may alternate often to give the handrail added strength. They are then bonded together using a suitable adhesive, which can be done using pressure, heat, or a combination of both!

After curing, the laminated structure can be curved into the desired shape using a bending jig or form. Once fully dry and shaped, the handrail can be finished in a number of ways such as sanding, staining, or painting.

As with the previous method of steam bending, laminating is also a time-consuming process, one which gets longer for larger and more complex designs. It also requires very specialised equipment such as clamps, jigs and possibly a vacuum press, which can be a significant investment for smaller suppliers. The thickness of individual layers can affect the overall strength and appearance of the laminated handrail; thinner layers may be more prone to cracking, while thicker layers can be more difficult to bend. The edges of individual layers must be prepared carefully to ensure a strong bond, as improper edge preparation can lead to weak joints and delamination. And again, there is also the environmental impact to consider, as the use of adhesives in laminating can cause the volatile organic compounds (VOCs) to be emitted during curing.

Visually, once a laminated handrail is finished, it will look a bit like a sideboard – as the glue lines will be visible. Similar to steam bending, it’s not a suitable technique for ‘ramps’, ‘corners’ and ‘scrolls’; suited mostly to large radius curves.

3D printing 

Also known as additive manufacturing, 3D printing involves adding layer upon layer of material to construct a digital design. It’s a way to create complicated structures, including curved wooden handrails!

Similar to the CNC machining technique, the handrail’s shape is first designed using CAD software, which is then sliced into thin, horizontal layers – these serve as instructions for the 3D printer. The printer then deposits the material, layer by layer, to create the physical object. There are a number of methods a 3D printer can use, including FDM (Fused Deposition Modelling), SLA (Stereolithography), and SLS (Selective Laser Sintering). Once complete, the finished handrail can be smoothed, sanded or painted.

There are restrictions that can come with 3D printing and creating curved handrails, most notably the types of materials that can be used, which will often be limited by their strength and durability, and therefore may not be suitable for the structural demands of a handrail. The aesthetics can also be impacted, as 3D printed objects will often have visible layer lines, and a rough surface finish which can require additional processes. Many 3D printing processes also require the use of support structures to prevent overhands from sagging which can add complexity to the printing process, and may need to be removed manually once the process is complete.

Size is a major issue when it comes to constructing curved handrails with 3D printing. Handrails can be up to four metres long – with our CNC machines being capable of constructing up to six metres – whereas 3D printing is designed for desktop-sized components. Curved handrails made in this way will also have no visible wood ‘grain’.

Frequently asked questions

Can you bend a handrail?

Absolutely! The methods above outline that it is possible to create a handrail that follows the curve and rise of your staircase. However, it must be done carefully to avoid damaging the timber.

How do you measure a curved handrail? 

Measuring a curved handrail manually is difficult and laborious, as well as being more open to errors! Here at Handrail Creations, we use 3D scanning and digital surveys to ensure all measurements are done quickly and accurately. All measurements taken are linked directly to manufacturing, and gives our team the ability to check the dimensions in ‘3D’ with the ability to modify or quickly redo in seconds.

If you don’t have a 3D scanner to hand or wish to measure manually, here’s what you’ll need:

• Measuring tape
• Chalk or marker
• Straight edge – such as a ruler
• Calculator

And here’s how it’s done:

• Identify where the handrail begins and ends, and mark the start using your chalk or marker
• Measure any straight lengths of the handrail and make a record
• To measure the curved sections, follow these steps:
  • Divide the curve into smaller sections to make it easier to measure
  • Use your straight edge to create a straight line between the endpoints of each section
  • Measure the length of that straight line
  • Measure the distance between the straight line and the curve at the midpoint of the curve section
• The calculate the length of the curve from these measurements, use the following formula:
  • Length of curve ≈ Straight line length + (Distance between line and curve)^2 / (2 * Straight line length)
• Add up the lengths of all straight and curved sections to determine the handrail’s total length

Now that you know how it’s done, have we inspired you to add something truly stunning to your home? For a handrail that’s completely bespoke to you, get in touch with the Handrail Creations team today.