Initiate's Sledgehammer

Taken all the way down to base materials, one Initiate's Sledgehammer is 2 crafting steps deep and needs 3 intermediates — Elm Lumber ×1, Fish Glue ×1 and Iron Ingot ×1 — which resolve to 3 distinct raw materials totalling 8 units, plus 5 crystals.

That bill outweighs 5,254 of the 13,602 recipes tracked here and 529 of the 1,932 Blacksmith ones, and 4,464 recipes nest deeper.

Only 2 of those crystals go into the final step; the other 3 are burned by the intermediates, so the real crystal cost is 2 Fire Shard, 1 Earth Shard, 1 Water Shard and 1 other kind.

The chain crosses three disciplines — Blacksmith to Lv 19, Carpenter to Lv 16 and Alchemist to Lv 10 — so no single class can finish it unaided.

All 3 raw materials are gathered, and not one of their spots is timed, so nothing in the tree waits on the Eorzean clock.

Of the intermediates, Iron Ingot has the widest use: 113 recipes call for it, spanning seven of the eight crafting classes.