Bolts

"This is sure to give a mechanical advantage"
There are 5 tiers of bolt:

Iron - Used in early game weaponry and necessary to craft the MegaCorpVendor, the station used to craft all the weapons from Rachet and Clank. 10 of these can be crafted from a single lead or iron bar on an anvil.

Meteorite - Used in mid-tier prehardmode weaponry. 10 of these can be crafted from a single meteorite bar on an anvil.

Hellstone - Used in crafting the best prehardmode weaponry. 10 of these can be crafted from a single Hellstone bar on an anvil.

Hallowed - Used in most hardmode weaponry. 10 of these can be crafted from a single hallowed bar on a mythril / orichalum anvil.

Luminite - Used in post-moonlord gear, the most powerful of all of the variants. 10 of these can be crafted from a single luminite bar on an ancient manipulator

Bolts are also a common drop from certain enemies, in prehardmode the Tyrranoid can drop iron, meteorite or hellstone bolts in decreasing amounts, this means that you will likely accumulate bolts over time so crafting them may not always be necessary.