Keep upgrading Weapons on Fine, until weapon is an AA-12 or Desert Eagle.Keep upgrading Keycard/Hacking Device on Fine, until keycard is level 6.Has a very high chance to destroy input items, and a lower chance to upgrade them by 2 levels.
For example: MTF Keycard + 1:1 = Hacking Device.
Output gives you an item of the same group, same level and value, just an item different from the input. Downgrades any input item by one level, destroys completely if cannot downgrade any more. Destroys any input items and biomatter. You get the rest, all in-game items have levels and chains, some chains short, like SCP-500, and some long, like Weapons. For example, Keycards: Level 1 > Level 2 > Level 3 > Level 4 > Level 5 > Level 6. To explain this one, imagine that every single item in the game, has "levels". The right chamber door will open in 9 seconds after you got teleported inside. If you had no items equipped ,it will do nothing. After those 4 seconds you will get teleported to the right chamber (Output) and it will modify the item you were holding, according to your setting. After you get in and the doors close, you have 4 seconds to equip the item you wish to modify. Press E on the light grey rotary switch located beneath the grey triangle (you will hear a clicking sound if done right) and quickly get inside the left chamber of SCP-914 (Input). (The recommended mode is Fine) The triangle's longer tip is pointing to the selected mode. Doing so will select the mode in which SCP-914 will be modifying input items. To use SCP-914, approach the control panel (at the middle), then press E to rotate the grey metal triangle. SCP-914, in-game, looks like a large clockwork mechanism, almost fully covered in thick steel plates, the main mechanism consisting of two chambers by the sides, and a control panel in the middle.