Speed vise - video

Nice idea. Using two half-nuts is probably close to the full strength of a full nut, most likely with full clamping force. Although, a 60 degree thread is a 30 degree ramp! I wonder if there is a tendency to dislodge when tightened? Other threads might be a better choice. A square thread would present a 90 degree face to the axial force. A left hand buttress thread (if there was such a thing) turned backward would also have a 90 face to the thrust line. Thanks for the post.