Pultruded Carbon Fiber Square Tube 2-10mm | 500mm Round Bore | HaoZhong

Pultruded carbon fiber square tube, 500mm long, with a round bore through the middle. Outside sizes from 2mm to 10mm.

Read the size code like this: the first two numbers are the outside, the third is the hole.

8X8X5MM means an 8mm square outside with a 5mm round bore.
10X10X4.5MM means a 10mm square outside with a 4.5mm bore.

Square outside, round inside. That shape is the point of this tube. A round tube rolls and needs a clamp or a flat plate to bolt against. A square tube sits flat on a surface, gives you four flat faces to drill or glue, and lines up square against another part, while the round bore still lets you run a shaft, a smaller tube, or a wiring loom through the centre.

Sizes

If you need a combination that is not there, ask. The bore is what changes most often, and we can usually supply a size that is not on the shelf.

About the finish

These are pultruded, pulled through a die in one continuous length rather than wrapped around a mandrel. The fibres run along the tube instead of being woven, so the surface is smooth and matte with no visible weave pattern. That is normal for pultruded stock and not a defect. Stiffness along the length is high, which is the main thing a pultruded section gives you.

What you get

Packs of 2 or 4 tubes, each 500mm long. Pick the pack size from the dropdown once you have chosen the size code.

Where we see them used

Drone and RC airframe spars, robot chassis rails, camera and sensor mounts, kite frames, and model boat or plane structures where a square section is easier to fix than a round one. Also used as a stiffener glued along a flat panel.

Before you order

• Check the code against the table above before you buy. 8X8X4MM and 8X8X5MM are different products, and the difference is the hole, not the outside.
• Cut with a fine-tooth blade or an abrasive disc. Take it slowly — a coarse blade will splinter the cut edge.
• Length is 500mm on every size listed here. If you need a different length, message us.
• Other sizes and lengths exist that are not listed. Ask before you assume we cannot supply it.

Square tube is pultruded, so it is worth being straight about what that means. Smooth matte surface with no weave, and a lower-cost fibre than our 3K roll wrapped tube. It is stiff along its length rather than strong in every direction, which makes it right for frames, jigs and light spars, and less right for anything taking real load. Where the part has to carry weight or resist crushing and twisting, the 3K roll wrapped tube range is the better part.