You can't smelt or forge a temporal gear. Your first one will usually come from harvesting a drifter, bowtorn, or shiver corpse. You can also buy one from a treasure hunter trader, though less often.
From drifters, bowtorns, and shivers
Kill the creature, then harvest its corpse. The gear doesn't drop when the creature dies; you have to harvest the body to get it. An ordinary corpse yields either nothing or one gear.
Surface drifters, surface bowtorns, and surface shivers all have the same chance of dropping a gear. Variants found deeper down have a higher chance. Bowtorns and shivers of the same tier have the same chance as drifters.
| Variant | Chance | About one per |
|---|---|---|
| VariantSurface Drifter | Chance2.7% | About one per38 corpses |
| VariantDeep Drifter | Chance3.3% | About one per30 corpses |
| VariantTainted Drifter | Chance4% | About one per25 corpses |
| VariantCorrupt Drifter | Chance4.7% | About one per21 corpses |
| VariantNightmare Drifter | Chance5.3% | About one per19 corpses |
Note: the hunter trait Resourceful increases this drop by a factor of 1.1. For a surface drifter, that brings the chance to about 2.9%.
From a treasure hunter
A treasure hunter trader sometimes has a temporal gear for sale. Roughly one in three carries it: each shop stocks 14 items selected from a larger pool, so the gear isn't guaranteed to appear. When available, only one is in stock. It costs 4, 5, or 6 rusty gears, with 5 being the most common price. No other trader sells it.
Rare finds
These methods aren't worth relying on for your first gear, as the chances of finding one are very low.
Panning bony soil gives you a 0.1% chance of finding a gear, while sand and gravel have a 0.05% chance. Each panning attempt yields only one item, making the actual chance of getting a gear even lower.
In an ordinary ruin chest, a randomly selected stack contains a temporal gear about 0.3% of the time. If one appears, the stack contains 1 or 2 gears. You can also find a gear already placed in the alchemist buried treasure, the Resonance Archives, and a few rare structures.
An immobilized eidolon drops an average of two gears when it dies. A double-headed drifter and a deepsplit shiver can appear in place of an ordinary creature only during a rare temporal storm. Each drops about one gear on average.
Usage
You can use gear to set your home point. For instructions, see the guide How to Set Your Home Spawn Point in Vintage Story. Holding a gear in one hand and a knife in the other restores temporal stability. The guide Temporal stability in Vintage Story explains this mechanic in more detail.
Later in the game, you'll need three gears to repair a broken static translocator. A clockmaker requires two, while the resonator requires one.
Wiki page: Temporal gear.