What are trammel heads?
|Trammel heads are marking out tools primarily used to draw large circles or arcs. They are sometimes called trammel points, or trammels.
|Together with a beam, usually made from wood or metal, trammel heads make up a beam compass. They are clamped a set distance apart onto the beam.
|Trammel heads come in pairs. Usually, one trammel head holds a pencil or other marking instrument and the other holds a steel point which anchors the tool to the surface being marked.
|They can be also be used with a metal or wooden ruler. This allows the trammel heads to be accurately set a specific distance apart. The distance between the trammel heads can be altered and will determine the size of the circle or arc that will be drawn.
|The radius of the circle that can be drawn with trammel heads is limited by the length of the beam they are used with.
|Trammel heads are usually made out of die-cast metals such as aluminium. This is because aluminium is lightweight, strong and resistant to corrosion, so trammel heads are likely to last a lifetime.