At least the small pieces, which receive the corners of the frame, should be made of hard wood such as maple.

It is self-adjusting but care must be taken not to buckle the parts of a narrow frame by over pressure.

It is well to soap or oil the corner pieces to prevent their being glued to the frame.
[Illustration: Fig.256.Gluing up a Column Joint.

(Pinch-Dogs at Top of Joints.)] In gluing together long mitered joints, in six or eight sided taborets or columns, in which the members meet edgewise, one method is to wrap a few turns of bale wire around the parts and drive in wedges under the wire to obtain pressure, Fig.256.Another method is to wrap a stout rope, such as is used for window weights, around all the pieces, properly set up, then to tighten it by twisting it with a stick thru a loop, Fig.257.A still more effective way is by means of the Noxall Column Clamp, a powerful device, used chiefly for gluing up such pieces as the pillar of a centrally supported table, Fig.259.

Care must be taken with all these devices to protect the corners, unless they are to be rounded off afterward.