My first project in technical collage for tool and die making was to make 1-2-3 blocks. I milled the blocks oversize to leave stock for precision grinding. After drilling and tapping the holes in the blocks, we case hardened them. The last process was to precision grind them to size. The grinding process involved both grinding to blocks to size and to a squareness tolerance.

1-2-3 blocks are blocks that measure one inch thick by two inches wide by three inches long. They typically come with an array of holes and some tapped holes for custom applications.

The blocks are used in the following applications in a machine shop:

• To setup CNC milling machines

• To setup manual milling machines

• To support a workpiece

• To setup a surface grinding machine

• To inspect machined parts

• To Touch off tooling for a reference