Most engines do not output either sufficient Torque or sufficient Speed to operate most machines. This is where Gearboxes come into play. Gearboxes have two modes, Speed and Torque. They default to Torque mode, and are swapped by shift-right-clicking with a Screwdriver. Gearboxes do not increase or reduce the power travelling down a shaft, they consume Lubricant to adjust the ratio of Torque to Speed on a shaft.
Gearboxes come in 4 levels, 2:1 4:1, 8:1, and 16:1. The level of the gearbox is the ratio of the gears, and the multipliers applied to the torque and speed they receive and output. To elaborate, when set to Torque mode, a Gearbox will take the shaft power applied to it, divide the input Speed by its ratio, and multiply the output Torque by its ratio. When in Speed mode, a Gearbox will do the opposite: divide the input Torque by its ratio, and multiply the input Speed by its ratio. So a 2:1 Gearbox in Torque mode placed on a shaft connected to a DC Electric Engine (4 Nm Torque at 256 Rad/sec) will output 8 Nm Torque at 128 Rad/sec.
Gearboxes can be made of Wood, Stone, Steel, Diamond, or Bedrock. The material of the Gearbox determines the maximum Speed and Torque it can handle, as well as its maximum Lubricant capacity. If a Gearbox receives or tries to output power at a Speed or Torque greater than these limits, it will fail, explode, and drop a small number of scrap items.
|Gearbox||Max Torque (Nm)||Max Speed (Rad/s)||Lubricant Tank (mB)||Scrap Dropped on Failure|
|Steel||6711||57005||24000||HSLA Steel Scrap|
As is shown, Wooden Gearboxes do not hold Lubricant. Wooden Gearboxes do not consume Lubricant, instead they heat up while in use. When a Wooden Gearbox reaches a temperature of 90C, it will start taking damage, and when it reaches 120C, it will catch fire and be destroyed. A Wooden Gearbox can be safely operated for roughly 75 seconds before it begins taking damage. Bedrock Gearboxes do not hold Lubricant because they do not consume it. Bedrock Gearboxes are infinite in strength and durability, through virtue of being made of Bedrock.
Every 80 Ticks, Gearboxes try to consume Lubricant. Lubricant is consumed based on the following formula:
(Difficulty Multiplier * log_2(TorqueIn) ) / 4
In English, Lubricant consumption is equal to the base 2 logarithm of the Torque entering the gearbox, multiplied by a Difficulty Multiplier and divided by 4. Difficulty Multiplier is determined by the configuration option I:"Difficulty Control". By default (I:"Difficulty Control"=2), Difficulty Multiplier = 1. If I:"Difficulty Control"=1, Difficulty Multiplier = 0.25. If I:"Difficulty Control"=3, Difficulty Multiplier = 2.5. So, in easy mode, Gearboxes consume Lubricant at 1/4 normal rate, while in hard mode, Gearboxes consume Lubricant at 2.5x normal rate. When broken with a Pickaxe, Gearboxes retain their stored Lubricant and damage.
When a Gearbox is in use but does not contain Lubricant, every tick it has a 1 in 40 chance of taking 1 point of damage and releasing a Crit particle. Each point of damage a Gearbox has taken causes it to void 1% of the Torque that enters it. Damage stacks multiplicatively and not additively, so 100 points of damage does not shut down a gearbox. However, as damaged gearboxes transmit less and less Torque, their usefulness is extremely limited. Damage is displayed as a percent via the Gearbox's GUI, or via its tooltip when held as an item.