After scorpion collecting last night in South Mountain in Phoenix, Arizona (June 28) it became apparent that the mechanism used to hold the scorpion down must not contact it near the end of its body as, when it strikes, it arches its entire body high above the ground. Therefore, the restrainment mechanism must be constructed to allow for this movement.
It does not seem likely that the restrainment mechanism will be able to work if the point(s) of contact are on the legs. First, it will be very difficult to strap individual legs down, and second, the legs may be too fragile to be take the force. Therefore, it seems the most appropriate location to contact the scorpion would be near its head (thus allowing for the body arching). Also, after the scorpion has been refrigerated it is quite docile, in fact appearing dead. This may be useful as when active the scorpions are quite fidgety and aggressive.
Due to the observations above, my initial design for the restrainment mechanism was a block of wood with a slanted top at the angle of the scorpion’s body when in a defensive (arched) position with a velcro strap. This way the scorpion could be in the correct position to sting and also be securely attached to the block.
A Google SketchUp version of John’s mirror box with my restrainment mechanism added:
The small slanted object at the bottom of the box is the restrainment mechanism (without the velcro stap, because it is extremely difficult to draw curved objects in SketchUp).