Metal-to-metal

Mr. T. Barnabas Daft, of Dublin, has just filed the specification of a patent for an invention which has for its object the forming of spigot and faucet ends upon cast iron pipes, true enough to make “metal to metal” joints without turning and boring.

Source: wiktionary

The cars would be all right with their good metal-to-metal brakes and anyway, coming down, they would not be loaded.

Source: wiktionary

Rubber shock-absorbing pads and bushes eliminate metal-to-metal contact and rubber springs are used for buffing and drawgear.

Source: wiktionary

The braking system of the latest units is largely of a new design, the components of which are smaller and lighter than before and in which many of the metal-to-metal contacts particularly subject to wear have been eliminated.

Source: wiktionary