Here's a quick reference on how to obtain each pickaxe in the current version (v1.2.18) of Industrial Pickaxes, in order of intended progression.

Enchanted Pickaxe
Bought from the Merchant after the Eye of Cthulhu has been defeated
Equivalent to the Gold Pickaxe

Blazing Molten Pickaxe
30 Hellstone Bars at an Anvil

Steampunk Excavator
Bought from the Steampunker after any mech boss has been defeated
Equivalent to the Adamantite Pickaxe

Graceful Chlorophyte Pickaxe
27 Chlorophyte Bars at a Mythril Anvil

Lihzahrdian Picksaw
A normal Picksaw, 10 Beetle Husk, and a Lihzahrd Power Cell at a Lihzahrd Furnace

Lunatic's Celestial Pick
15 Luminite Bars and 9 of each lunar fragment at an Ancient Manipulator

Eclipsium Eviscerator
15 Eclipsium Alloy, made with a Hallowed, Chlorophyte, and Luminite Bar each, both at an Ancient Manipulator

Means to an End
An Eclipsium Eviscerator, 35 Eclipsium Alloy, and one of each previous industrial pickaxe at an Ancient Manipulator

Hope this is helpful!