The ornamental design for a stringgroovemasonryclamp, as shown and described.
FIG. 1 is a top perspective view of a string groove masonry damp showing my new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a left side elevation view thereof;
FIG. 4 is a front elevation view thereof; and,
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a rear elevation view thereof;
FIG. 7 is a bottom plan view thereof;
FIG. 8 is a bottom perspective view thereof; and,
FIG. 9 is an environmental view thereof.
The broken lines showing the masonry block and string are for the purpose of illustrating environmental structure and form no part of the claimed design.