These lines have an extended metaphor that refers to a blacksmith and his tools. The tools make up the extended metaphor of the creator and and his creation of the Tyger.

"Did he who made the Lamb make thee?" - The Tyger by William Blake

When the Lamb is mentioned, it is an allusion to Christianity.

"What the hammer? what the chain?

In what furnace was thy brain?

What the anvil? what dread grasp

Dare its deadly terrors clasp?"

- The Tyger by William Blake

"And what shoulder, & what art,

Could twist the sinews of thy heart?

And when thy heart began to beat,

What dread hand? & what dread feet?" - The Tyger by William Blake

The author mentioning body parts, such as the shoulders, hands, and feet, are an example of a synecdoche.