227, vary in size and shape according to their use; as, flat-headed, gimp, round-headed, and double-pointed or matting tacks, a sort of small staple.

Their size is indicated by the word "ounce." For example, a two-ounce tack is 1/4" long, a three-ounce tack is 3/8" long, a four-ounce tack is 7/16" long, a six-ounce tack is 1/2" long, etc.

This term once meant the number of ounces of iron required to make 1000 tacks.
Tacks are useful only in fastening to wood thin material, such as veneers, textiles, leather, matting, tin, etc.

Tinner's tacks, which are used for clinching, are commonly called clinch-nails.

Wire tacks, altho made, are not so successful as cut tacks because they lack a sharp point, which is essential.
[Illustration: Fig.228.Corrugated Fastener.] _Corrugated fasteners_, Fig.