A thumbstick for a user input device comprises a tiltable post operable to output a control signal based on its position, with the post comprising external threads and a post anchor feature. An adjustable tensioning mechanism is configured to modify a tilt tension of the post. A cap comprises a cylindrical stem that defines a cavity. A base is moveable with the post and comprises a first cylindrical portion extending into the cavity, and a second cylindrical portion comprising internal threads and a base anchor feature. The internal threads mate with the external threads of the post to fasten the post to the base, and the base anchor feature abuts the post anchor feature to prevent displacement of the base toward the proximal end of the post.