An ultra-precise boring cartridge and an adjustment device is disclosed. The boring cartridge includes a cam, a cam follower contacting the cam by a sloped portion, and a spring arrangement exerting a biasing force against the cam follower. The adjustment device includes a graduated dial affixed to an annular sleeve having a hexagonal-shaped end engaged with the boring cartridge. In an embodiment, a dial of the boring cartridge is rotated in increments of about 3.6° by the adjustment device, which causes movement of about 0.005 mm of the cam in a X-direction and movement of about 0.001 mm of the cam follower in a Y-direction, thereby selectively adjusting a machining radius of a cutting insert mounted on the cam follower.