All construction tips for a key clamp structure
Projects made from tubes and key clamps are highly versatile, allowing you to build anything from furniture to industrial structures. With a wide range of products, you have the flexibility to create your ideal design.
We frequently receive questions about assembly, material selection, and choosing the correct tube diameter or length. In this blog, we’ve compiled practical construction tips to help you get started.
Key Clamp Tubes
Choosing the right keyclamp tube diameter
The larger the tube diameter, the stronger the tube. However, selecting the correct diameter depends on several factors, such as the weight the structure must support and the length of the spans.
For railings and safety constructions, a 42 mm or 48 mm tube diameter is the standard, as these sizes comply with regulations regarding length and load-bearing capacity. For tables, a 42.4 mm tube diameter is often used, while for a clothes rack or coat rack, a 26.9 mm diameter is more common. We’ve outlined the most frequently used tube diameters for popular structures in a separate guide.
Maximum Tube Span Guide
Below is a guideline for the maximum span of steel tubes. The span of a tube refers to the distance between two support points of a horizontal tube. The maximum span can vary widely, and there is no definitive answer.
We recommend limiting the span as much as possible. If necessary, add extra support posts for structures like free-standing railings or use additional brackets for curtain rods or a railing mounted to the wall.
| Diameter | Maximum Span |
|---|---|
| 26.9 mm | up to 150 cm |
| 33.7 mm | up to 200 cm |
| 42.4 mm | up to 250 cm |
| 48.3 mm | up to 300 cm |
| 60.3 mm | up to 350 cm |
This is just a guideline, so a larger span is possible if there's little weight (<50 KG) on the span. If a significant weight is expected (150+ KG), we recommend reducing the span.
How to Determine the Right Tube Length
How do you determine the right tube length? This is a frequently asked question. Determining the correct length depends on the design and the materials used.
Some key clamps affect the tube length. For example, the base plate has a flange thickness to consider. Deduct about 1 cm per base plate from the total tube length. The tube still has a few millimeters of play within the clamp itself.
For certain nstructions, it’s essential to know how far a tube goes into the clamp, such as with a 2-way or 3-way elbow. In the full guide “Calculate the required tube length for key clamps”, you can find detailed calculations on how to do this accurately.
Allowing for Play in the key clamp
This aspect was briefly mentioned above. It’s good to know that most clamps allow for a bit of play. The tube doesn’t need to be fully inserted into the clamp.
If you want to mount a tube tightly between two walls with base plates, like for a coat rack or curtain rod, you can order the tube 1 to 2 cm shorter. The tube can then slide out slightly from the base plate during installation, ensuring a perfect fit while allowing minor adjustments during installation.
Connecting tubes securely using a connector
If you need to connect two tubes, use a joint connector. Only use this when it’s not possible to work with full-length tubes, full-length tubes offer more stability. Internal connectors provide a more seamless look but are slightly less sturdy than external ones.
To add extra stability, connect crossing tubes at the joint. For an upright, through-standing tube, you can use a 1-way cross. At the end of a standing tube, you can use a long tee fitting.
Assembling Your Structure
Mounting tubes into key clamps
Tubes are secured into the clamps using an allen screw. This allen screw has a cutting edge that locks into the tube when tightened firmly. The allen screw is included with the key clamp. Always use the correct Allen key size to avoid damaging the screw.
Bolts and screws
Many clamps have pre-drilled holes for mounting onto walls, floors, ceilings, or wooden surfaces. For example, base plates and handrail brackets require secure attachment to ensure stability. If the correct advised bolt is available in our assortment, it will be listed under the "You might also need these" section.
Tips for building key clamp furniture
Storage unit
A key clamp storage unit is usually made with shelves. Shelves can be mounted in different ways. You can use single or double fixing rings. Slide the ring over the tube, and secure the shelf onto the plate of the clamp (for example, with carriage bolts). Another option is to let the shelf rest on the flange of a base plate or on a retaining ring.
Clothing rack
For a clothing rack, avoid tube diameters larger than 33.7 mm, as most hangers won’t fit around the tube. The 26.9 mm or 33.7 mm diameter are most commonly used. If the rack will hold a lot of clothing, ensure adequate support points. To prevent sagging, ensure adequate support points, especially if spanning more than 2 meters.
Table
You can mount a tabletop to the frame using base plates or fixing rings. For a heavy tabletop, you can simply lay it on the frame. If the top isn’t supported on all sides, a sturdy tabletop is essential to prevent warping over time.
Handrail
The appropriate tube diameters for a (home) handrail are 26.9 mm and 33.7 mm. We offer two types of handrail brackets: closed and open inlay. Use two brackets for a standard handrail. For longer spans, around 2.5 meters or more, use three handrail brackets.
Need Help?
If you have any questions about product selection or assembly, feel free to call or email our customer service. We are happy to assist you!
