Cutting Corners

Most individuals, observing the mouldings of the broken-arched cabinet cornice and longcase clock hood below could be forgiven for thinking “What handsome/hideous mouldings” without realising the technicalities involved with the mitring of the arches and flanking straight mouldings.

Straight and curved cornice moulding on bureau bookcase, c.1710 (Millington Adams)

Longcase clock hood with broken-arch moulding, c.1770. (The Clock Workshop)

To even the keenest eye, the straight sections of moulding appear to be mitred at 45° where they meet the curved sections, however, it’s not that straightforward. The intersection of curved and straight fielding on the panel below clearly illustrates there is something else going on.

Straight and curved fielding on mule chest panel, c.1762. (Tim Bowen)

In A George III Mahogany Cabinet-on-Chest Redux, reader, Confur, commented (quite correctly) that to mitre a curved section of moulding with a commensurate straight section one must curve the mitre. This has since raised a few eyebrows, so I offer the following explanation.

With any juncture of mouldings, whether straight-to-straight, curved-to-identically-curved or curved-to-straight, all the mouldings’ elements must obviously intersect precisely for appearance’s sake. For straight-to-straight and curved-to-identically-curved mouldings, the mitres are, as one might expect, straight, however, with curved-to-non-identically-curved or curved-to-straight mitres, a ‘hunting’ mitre must be cut to ensure all the elements coincide.

The diagram below (click on it for an enlarged view) depicts a curved moulding and a straight moulding such as might be found in a cabinet cornice or longcase clock hood. The mouldings’ elements or ‘nodes’ can be seen to intersect each other.

To establish the cut line for the mitre, a solid line has been drawn from A to B such that it intersects each node. By comparison, a second, broken, straight line has been drawn from A to B which clearly does not intersect the nodes.

Hunting mitre.

While, technically, a hunting mitre is required to accurately join a curved moulding with a commensurate straight one, narrow astragal mouldings such as employed on the doors of the George II Mahogany Cabinet on Chest are more often than not simply mitred at a nominal 45° as the human eye is incapable of picking up the irregularities on such a small scale.

Straight-mitred astragal mouldings.

Jack Plane

Advertisements

About Jack Plane

Formerly from the UK, Jack is a retired antiques dealer and self-taught woodworker, now living in Australia.
This entry was posted in Furniture Making and tagged , , , , . Bookmark the permalink.

2 Responses to Cutting Corners

  1. Tico Vogt says:

    In the example of the moldings on the large clock, how would one go about creating those curving miters? Carving?

    Like

    • Jack Plane says:

      I’m not a trained cabinetmaker, but the method I use is to pare the convex element with a chisel and pare the concave element with a gouge, comparing them frequently against full scale drawings.

      Like

I welcome your comments

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s