I can’t remember where I first saw one of these but they are often not used or known off by film makers now.  The camcorder rocker is used to produce tilt shots when a tripod or hi hat cannot to placed within an awkward location.

0:03 Draw circle and mark Centre clearly.  The size will depend on the side of the camcorder you want to use.
0:29 With a router I cut out the circle, using the centre point and guide rail supplied.  However this can be cut with a router.  Normally I prefer to drill a hole and use a bold to centre the router but this time I hammered the centre point into the sheet material.
0:49 I used a large weight and a clamp to hold the sheet over the end of the workbench while cutting the last part to free the circle.
1:07 Hand sanding the circle a little.
1:20 http://youtu.be/2Is4AmNsUFM  I didn’t have to use this technique considering the router left behind a central point, however had you used a tin of paint as a template you would want to know this technique to work out how to section the circle.
2:01 Mark the circle into thirds.
2:24 Cut the section out making sure to cut on the same side of the line you draw to keep the segments identical.
2:38 Give them a rock on a level surface to see if they are identical.
2:56 Using a marking gauge to mark the centre of where the pieces will join.
3:30 Hammer in some nails and clip them to a few millimetres.  This will be used to mark the segments and line up the holes that are about to be drilled.
4:22 Label.
4:55 Drill holes for dowel using a bit of tape as a depth stop.
5:20 I made these a little too tight in retrospect.  There is a good video by Matthias Wandel http://youtu.be/14Mkc63EpMQ who demonstrated that tightly glued pieces hold with less strength than those with a little gap.  I had to hammer the pieces together and accidently marked the upper side of the camcorder rocker.
5:55 Drawing, scoring and punching a pattern to the top of the rocker.
6:44 Cleaning.
6:54 The rocking motion.