In this new series of blogs we wanted to answer some of your questions that couldn’t be covered in enough depth on our FAQ page.
The first blog will cover our tube clamps and tube; some clarification on their diameters and how the sizes translate from metric to imperial.
Tube clamps come in a variety of sizes for different sized metal tubes: 17.5mm, 21.3mm, 26.9mm, 33.7mm, 42.4mm, 48.3mm and 60.3mm outside diameter. (Please note that some manufactures and retailers may quote these numbers slightly differently, give or take 0.2mm, so rest assured if you see tube clamps marked as 33.9mm, they are for the same tube as another company’s 33.7mm.)
What are the sizes of the tube clamps that can be bolted to Domino Clamps?
As explained in a previous blog detailing how to attach a scaffold tube to a shipping container, we use Interclamp’s 48mm, 42mm, and 34mm vertical tube clamp (also known as palm railing) fittings to easily attach 3 common sizes of steel tube vertically to a shipping container.
We also stock horizontal tube clamps (also known as a base railing flange tube clamp) both with and without a kick plate attachment for 48mm, enabling a tube to be attached horizontally to a shipping container. This may come in handy if you want to hang a sign at the same height as the shipping container and you have containers that are stacked on top of each other.
Finally we have horizontal (parallel) tube clamps for attaching a steel tube along the length of a container for hanging decorative or advertising banners. It could also help provide a bottom horizontal fixing point for a handrail system around the top of a container.
However both these options are only available in 48mm versions.
The tube clamp spec says 48.3mm, why have you shortened it to 48mm?
The tube clamp sizes have been rounded to the nearest whole number, this makes it easier to understand. Interclamp does the same in their product part numbers.
What diameter tube will the tube clamps actually fit inside?
Tube clamps are made to suit steel tubing to BS EN 10255 (ISO 65), medium to heavy gauge, also equivalent sizes of tubing in other materials.
Tubing of other specifications can be used, providing the steel is compatible with BS EN 10255 (ISO 65) and the wall thickness is not less than 3.2mm
This means that 48mm tube clamps won't usually accept 50mm diameter ERW steel tubes as they are just a fraction too large. This also tends to be too thin walled as well, so we recommend using the correct size; standard scaffold tube.
What is the equivalent in US sizes?
In the US, tube sizes refer to the bore size (inside diameter) of the pipe and not the outside diameter. This is laid down in the standard of Nominal Pipe Sizes (NPS). The metric European Version, Diamètre Nominale (ND) is equivalent to these. So our 34mm is the equivalent of 1” NPS , 42mm is 1 ¼” NPS and 48mm is 1 ½ “ NPS.
The reason we (Europe) have strange and very specific outside diameters for our tubes is to maintain compatibility with the older imperial system of NPS.
Can I buy the tube clamps directly from a US stockist?
Unfortunately, not at the moment. We are currently looking for a US stockist of tube clamps which will fit our Domino Clamps, for the moment, you can see all our tube clamps in the shop, which should show you prices in US dollars if you are in the States.