First appearing in Chapter 1: Moving Pictures, the gear is one of the six items needed to fix the Ink Machine. The gear can be found in the chest on the Ink Machine's room balcony when finding one of the dry cells but was not obtainable at first until Henry starts the quest on finding the required items.
A lot of gears reappeared in some of the chapters:
In Chapter 4: Colossal Wonders, the gear is one of the objects that the Ink Maker can print. In the "Repair The Bridge" objective, the gear must be printed to fix the cart for Henry to across to the other side. Two can also be found in front of Henry at the very start, in Accounting & Finance.
The gear at the table while Tom is on guard.
In Chapter 5: The Last Reel, an unobtainable gear can be found leaning against under the table inside the starting location of the prison area where Allison Angel and Tom kept Henry in prison for few days at the beginning of the chapter. Few gears are also seen being used as steps for Ink Bendy's throne chair inside the throne room.
Trivia
The gear resembles the pre-existing gears used for the Ink Machine's prototype model.
Until the release of Chapter 4, the gear was found randomly in several locations from Chapter 1.
Ink Machine Room: Found randomly on either both wall sides in the location's earlier build.
Corridor Paths: Away from the mini workroom area, it is found leaning against the bench next to Bendy's cutout.
