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Tube Endforming

We are guessing that there are two reasons you may want to form the end of a tube:

  1. TO CREATE A MECHANICAL FIXING - This can be between the tube and another piece of tube, or with another component, and it can be permanent, semi-permanent or temporary. There are various options to consider for these different cases.
  2. TO PROVIDE A LIQUID TIGHT SEAL JOINT FOR FLUID TRANSFER - This can be between the tube and another tube, hose, manifold or fitting. These typically involve some type of flaring of the end of the tube and are what people often mean when they use the term “end-form”.
  1. NOTCHING
    Often known as cod-mouthing (due to the shape which is reminiscent of a fish’s open mouth) when performed on the end of the tube. This is commonly used when tubes are to be permanently joined together as part of a welded or brazed fabrication. The angle and diameter of the cut can be altered to suit. Tubes can be notched along their length also.

    This end form can also be used for a semi-permanent fixing by welding a nut inside the notched end and drilling a hole through the other tube. A bolt can then be passed through the hole and screwed into the nut. This is often used in furniture joints.
  2. MITRE CUTTING
    The end of the tube can be cut at any angle up to 45 degrees on a cold saw; past this angle it would require machining. Tubes are usually mitre cut after bending. It is also possible to cut through the bend.
  3. FLATTENING
    This method involves flattening the end of the tube. For mechanical/structural applications, there may be a hole drilled through to allow securing to whatever it needs to be attached to. The corners of the flattened piece can be chamfered or rounded off.

    This appears to be a very simple end form, but just hitting the end with a hammer will not produce a very attractive result. To produce a repeatable form, a fly-press, or better a hydraulic press, is needed. For best results, especially where an aesthetic finish is needed, a shaped press tool is required. Sometimes, these tools can be 3D printed, thus keeping costs to a minimum whilst producing a great looking form.

    This end form is often used for structural purposes, and it is also possible to flatten a tube partway along, possibly even after bending, for more complicated structures.

    Flattened ends can also be used as nozzles or sprayers.