I have noticed slight cracks appearing around the camera thread mount in the base of my Qumi (I have it upside down, suspended from the thread mount). At first I thought these were simply the weight of the Qumi hanging from the thread insert, but now I realise they are because the mount is not in line with the centre of gravity of the Qumi, so there is a torque being applied continuously.
The torque can be relieved crudely by adding counterbalance weight, but this adds to the force being applied to the thread insert. My recommendation is to add a baseplate (eg plywood) the same size as the Qumi footprint, secured to the thread mount with a 0.25" Whitworth screw and a spacer, so that the existing rubber feet are in contact with the baseplate and remove the torque on the thread insert. The spacer on the screw is to prevent the screw being tightened beyond the stand-off created by the rubber feet (otherwise over-tightening could "extract" the thread insert).
A replacement camera thread mount can be provided by drilling and tapping a hole in the plywood baseplate in line with the centre of gravity (this will make it easier to suspend the Qumi without it wanting to twist the mounting). This is easily done by drilling the hole slightly undersize (eg a 5.5mm diameter instead of 6.5mm) and then screwing a 0.25" Whitworth bolt into it to cut the thread. However, with a plywood baseplate, many other mounting options become available (eg magnetic catches). The fastidious may want to let in a proper metal thread insert (eg glue a nut into a counterbored hole with epoxy resin).
Edited by crashbot - 8/18/13 at 3:31am