Used in this way they are very convenient for marking out chamfers, especially on curved edges, a sharp pencil being substituted for the steel point.
The _beam-compass_, Fig.

208, consists of two _trammel-points_ running on a beam which may be made of any convenient length.

It is used for describing large circles.

A pencil may be attached to one point.
_Calipers_, outside and inside, Figs.

209, 210, are necessary for the accurate gaging of diameters, as in wood-turning.
[Illustration: Fig.207.Winged Dividers.] [Illustration: Fig.208.