Bendywood® bending handrails are:
- in solid hardwood
- in full sizes / not in multiple layers
- already machined, ready for bending
Our stock product range contains:
Bendywood® handrails can be bent up to a radius of 20 times the profile's cross section. A 40 mm round profile up to a radius of 800 mm, for instance, and a 50 mm profile up to a radius of 1.000 mm.
In order to be able to bend up to these limits a wood moisture content of about 12% is indispensable.
See part 2. How to bend Bendywood® and moisten it if needed.
Attention: Bendywood® will slightly open up when taken off the mould. Therefore, in order to obtain the requested final radius, Bendywood® needs to be “overbent”, i.e. the radius needs to be kept proportionally smaller. Also see on our website under “Spring-back after being taken from the mould”.
BENDING JUST BY HAND:
- Use the steps of the staircase as a bending mould for bending an exterior handrail, if sufficient space is available to do this: bend on the steps on the inside of the railing and mount on the railing, as the curve will slightly open up when the handrail is taken down from the steps.
- Bending an ascending handrail around a flat mould:
this is the easiest and best solution for spiral staircases!
See video for a round handrail:
See video for a round handrail with flat bottom side:
NEW: such already bent and ready-to-mount bending handrails are now available on request:
- The transport costs are significantly lower than the costs for shipping long straight sections.
- It is possible to perform the upwards bending later, when mounting the bending handrail.
- It is also possible to combine normal wood with Bendywood®.
- Also lengths up to 13 m are feasible, as special production.
- Handrails with groove/plow are also possible.
The following video shows how such a handrail is installed upwards:
- Bending an ascending handrail around an ascending mould / assembly support:
In case it is not possible to use the staircase itself as bending mould, you can build a mould as shown in the above video and pictures.
Keep the radius about 10% to 20% tighter than the requested final radius, as the bent handrail will always "open up" when taken from the mould.
BENDING BY USING A RING ROLLING BENDING MACHINE:
- Solely the bending handrails with diagonal joints can be pre-bent with a ring rolling bending machine (up to a radius of 1 : 30), as only diagonal joints can endure the mechanical stress of a bending machine. A handrail with a diameter of 40 mm, for instance, can be bent up to a radius of 1.200 mm. The final bending - if necessary - up to a radius of 1 : 20 should be carried out by hand around a mould or on the banister. See the following video to this:
- Tighten the bending radius progressively, letting the handrail run through the rollers of the bending machine not more than 3 times. Bear in mind that the ring rolling bending machine also rolls the wood and rolled Bendywood® will reach its limit of flexibility more quickly. Consequently, a 40 mm thick handrail, for instance, can only be bent up to a radius of 1.200 mm by machine, then you should continue by hand.
- The bending handrails with normal joints CANNOT be bent with a ring rolling bending machine.
HOW TO BEND NON-ROUND HANDRAILS UPWARDS ?
All handrails turn on their own axis when being bent upwards. This torsion is not visible in case of a round handrail, as a round profile always looks the same when turned. In case of other profiles or round profiles with a groove/plow it is necessary to compensate for torsion, so that the lower part of the handrail remains below.
It is best to proceed as follows: (in one operation cycle)
First of all bend the handrail on a flat mould. Then clamp it onto the banister (which ideally has a flat steel strip or similar) starting from above. The "turning" should be carried out using a long-arm clamp, which needs to be clamped onto the handrail at a distance of 1,5 m in order to have sufficient leverage. Turn and fix the handrail little by little until the entire handrail rests on the banister.
A few days later – after it has stabilized – the handrail can be taken from the banister to be sanded, stained and varnished. Proceed as soon as possible with the permanent fixing, so that the handrail does not lose its bent form.
Thick sections (such as omega handrails or 60 mm thick round sections, for instance) need to be cut in half, after which both halves need to be bent, turned, glued and clamped onto the banister in one operation cycle. Always use glue with a long open time! In this regard also take a look at our website under:
FORMULA FOR CALCULATING THE LENGTH OF A SPIRAL STAIRCASE HANDRAIL:
- 18 steps
- Step rise: 17 cm
- Step run beneath inner handrail: 13 cm
- Step run beneath outer handrail: 40 cm