Strike: From blow to smooth finish

Outside the building site, to strike is to deliver a blow: a fist strikes a face, a match strikes a box, a clock strikes the hour. The word carries force, impact, a sudden application of energy.

In construction, a mason strikes a joint by drawing a tool across the mortar between bricks or stones after it has been packed in place. The tool, often a striking iron or pointing tool, is drawn downward or slightly inward along the seam. This cuts away excess mortar and compresses what remains, creating a neat, finished edge that sits exactly flush with the wall face or recessed at a controlled angle. The result is both structural and aesthetic: the compressed mortar is denser and less prone to water penetration, and the joint line is clean and professional. A downstrike, related to this work, fills and finishes the bottom of a joint by pressing mortar firmly inward from below.

Metallurgy shares a different industrial sense of strike. To strike hot metal, especially iron, is to shape it with hammer blows while it remains hot enough to be plastic. Here strike retains its sense of impact, but the timing is critical: strike while the iron is hot, because once the metal cools it hardens and becomes difficult or impossible to work. The metaphor has entered common speech, but in the forge the technical meaning is precise and urgent.

The masonry sense diverged from the physical meaning of strike through the tool itself. When you drag a striking iron across wet mortar, you are technically striking it: you are hitting it with force, though the force is linear and controlled rather than sudden. The tool strikes the joint. Over time the focus shifted from the tool's action to the resulting finish, and strike came to mean the end product: a struck joint, meaning one that has been smoothed and compressed. In metallurgy, by contrast, the word never lost its basic meaning of deliberate impact; the emphasis on timing comes from the physics and metallurgy of the material, not from any shift in the word's sense.