Multi-Purpose Square. The maker of the Combination-3D try square claims that it can do the work of a saddle square, a marking gauge, a bevel gauge, and a combination square — with no loss of accuracy. Hand-made in England, the tool is cast from aluminum stock and has a Sheffield steel blade that’s factory-set to a tolerance of less than .01 degree over its length. If the C3D is dropped from, say, a scaffold, the blade can be reset or replaced. The tool costs $50. M. Power Tools, 613/525-3328, mpowertools.com