Image of a needle point tracing wheel from MacCulloch & Wallis»
Tracing wheels usually have a blunt edge, a serrated edge or comes in a needle point style wheel on a wooden or plastic handle. They are used for transferring markings between patterns, or between patterns and fabric. The example tracing wheel in the image is an example of a needle point tracing wheel, and is also ideal for tracing markings from toiles back onto patterns in order to make pattern adjustments.
The blunt ones can be used for tracing with carbon paper to mark off one pattern onto another paper or piece of cardboard.
The serrated or spiked wheels are the ones most commonly used in pattern making which pierce a line of small holes through from one layer of paper or cardboard onto the layer underneath.
Tracing wheels also allow you to trace off sections of toiles which you have draped on a mannequin onto paper or cardboard for a final pattern.
Tracing wheels can also be used when cutting out your fabric and marking details. Blunter style tracing wheels can be used with carbon paper directly onto fabrics to mark outlines and markings where needed, such as for dart arms or pleat placements. Always check that your wheel is not damaged first to avoid damaging your final fabric.
Note: This post was updated with a new tracing wheel link on the 5th July 2019.