A self-centering vial clamp is provided. The self-centering vial clamp includes a clamp body including a vial aperture and two or more jaw slots spaced around the vial aperture, two or more clamp jaws spaced around the vial aperture, with a clamp jaw including a vial contact face and one or more jaw projections configured to engage a jaw slot of the clamp body, and two or more lever arms coupled to the two or more clamp jaws. A lever arm of the self-centering vial claim is configured to be manually pivoted, wherein the lever arm translates the pivoting motion into a sliding motion of the corresponding clamp jaw. Interacting lever gears formed on the lever arms constrain the two or more clamp jaws to move substantially in unison during the manual pivoting, aligning the vial.