Mesh designates the number of openings and fractional parts of an opening, per lineal inch. To determine the mesh, count the number of openings from the center of any one wire to the center of a parallel wire, one inch in distance: Figure #1 illustrates a four mesh count. When the point an inch distant from the center of a wire falls between wires, the mesh count is expressed in fractions. Figure #2 illustrates a 3-112-mesh count. (3-112 openings from center of any wire to a point one-inch in distance.) When two parallel wires are on centers of 518″, 314″, etc., they can be expressed as 518″ mesh, 3/4″ mesh, etc.

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Fig. #1
6X6 Mesh
.063″ Dia.

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Fig #2
4-1/2  X  4-1/2 Mesh
.063 Dia.

Fig #3
5/8″ Mesh
.177″ Dia.

Space
“Space” is the actual “clear opening” or space between inside edges of two parallel wires.  It should be carefully differentiated from the terms “Mesh.” see above

Fig. #4
1/8″ Space
.092″ Dia.

Fig. #5
3/8″ Space
.135″ Dia.

Fig. #6
1/2″ Space
.125″ Dia.