Spherical panorama tripod head for Sigma 10-20mm lens

Update: I added PanCam_PanBaseA_45.stl to the files, this base snaps every 45 degrees instead of 30 degrees, it works better to do panoramas with the camera in portrait position.
Here's a link to a spherical panorama taken with this tripod head: https://ssl.panoramio.com/photo_explorer#view=photo&position=0&with_photo_id=114493851&order=date_desc&user=8522613

Another one: https://ssl.panoramio.com/photo_explorer#view=photo&position=0&with_photo_id=114526388&order=date_desc&user=8522613

This is a tripod head to take spherical panoramas using a Sigma 10-20mm lens.
The head rotates the lens around the focal point, so that there is no perspective distortion; it also has a 30 degree snap rotation mechanism for the panning and a 30 degree increment (from -30 to +45 degrees) ratchet for the tilt to make taking each exposure, well, a snap.
It needs a bunch of M3x20 countersunk screws (plus one 25mm long one for the clamp hinge) a couple M6 bolts for the tilt axis and two M5 bolts for the clamp tightening screw and the base screw.
The latches need a spring, 5mm in diameter and around 2cm in length, I suppose the spring from a pen could work.