Hephaestus is god of fire, craftwork, volcanoes, and more. He is a smithing god. He has the skills to make well measured decisions in what he makes and what he does. He is the god of gear. He made equipment for the gods; e.g., Helios' chariot, Eros' bow and arrows, Hermes' winged helmet and sandals. There are connections between the story of Hephaestus and the being of gear in relation to world.
Harman (2011) takes the spade as the sign of a real object. He does this in relation to the four dimensions of the fourfold. The real object subsists veiled. It is withdrawn. It is ready-to-hand. Harman (2007) interprets ready-to-hand as "the type of being possessed by tools. When things are ready-to-hand, they tend to withdraw from explicit views. At any given moment we use countless items of equipment: oxygen, floorboards, heart, kidneys, hammers, and computers. These things are rarely present to us. As long as they are working effectively, they tend to remain invisible. We usually notice them only when they break, turn up missing, or function badly" (2007, p. 176-177).
Heidegger's example was the hammer. My example has been the y key. The y both literally and figuratively withdraws in use. It figuratively withdraws as a member of keys in the keyboard tool and it literally withdraws as a particular tool as the y key. "The peculiarity of what is proximally ready-to-hand is that, in its readiness to hand, it must, as it were, withdraw [zuruckeziehen] in order to be ready-to-hand quite authentically" (BT, p. 99). "The kind of being which equipment possesses--in which it manifests itself in its own right--we call 'readiness-to-hand' [Zuhandenheit]" (BT, p. 98]. Readiness-to-hand is subsistence. Withdrawl is being veiled. The y key is veiled until it breaks down as if it were to be tapped and not depress in its role. It would then be unveiled in the occurrence of its malfunction.
But what of Hephaestus? How is the tool god related to veiled withdrawl or unveiled breakdown? In his 1980 essay about Hephaestus and introversion in a collection of work connecting the psyche and mythology, Stein makes the case that the god of smiths "is a quintessential fringe-person [veil-person] on Olympus" (1980, p 67). Hephaestus keeps his forge and fire deep within the earth. He withdraws with his tools to practice his craft. As a smith, he stands in service of the metallurgic events about the furnace. When Hephaestus was born his mother, Hera, flung him into the sea where he was rescued by sea-nymphs who took him to mukos, or the withdrawn place, "the innermost place" (Stein, 1980, p. 73) for nine years. After emerging through birth he again withdraws to the order of nine (gestation). He forges tools in the earthbound background. Equally, Heidegger associates the earthbound background with the veiled subsistence, that is, the withdrawn readiness-to-hand.
The work of Hephaestus at his hearth, skillfully dealing with his tools while crafting tools relates to veiled subsistence. What then, of unveiled subsistence? How does Hephaestus reveal anything of that? Hephaestus himself is an example of breakdown. A common epithet is "the lame" or more to my point Kullopodiou , i.e., clubfooted. Unveiled subsistence is the dimension of mortals. Harman (2011) has it as realm for the sensual object. It should be no surprise then that he signifies this with the club. Hephaestus' feet are malfunctioning gear. They are broken down. In this breakdown attention is drawn to them. Just as when the y key fails to depress, when it does not witdraw in the role it plays it calls our attention to its qualities; so does Hephaestus "amphigueis " (the lame one) call attention to himself. The feet of Hephaestus ineffectually play their role and as such "tell volumes: they are turned back to front, and when he walks he goes with a rolling gait that strikes the other gods as somehow hilarious and breaks them up with mirth" (Stein, 1980, p. 68).