The Arm Tubes are constructed from 4" thick walled PVC pipe.  There are two straight sections and one 45 degree section for each arm.  The concept is to allow for a bit of bend in the bottom's elbow, some rotation in the shoulder, and some wiggle room inside the tube for the entire arm.   By doing these things, we prevent the bottom's arm muscles from cramping.  In practice, we have found it quite frustrating to have arm movement, but still have no chance of escape.


Note that the short straight section of each arm tube is not cemented to the angled section. This is because some folks would not be able to insert their arms if the parts were rigidly connected.  In the image above, one of the tubes is placed upside down so you can see the holes that are used to secure the tube to the threaded rod.  Several holes have been drilled, to provide for adjustability.


In the images below, you can see how the tubes are mounted to the table.  A single table strap is used around each 45 degree section and the ends are supported by the threaded rod.  A small hole has been drilled in the ends of each of the two threated rods so that a padlock can be used to prevent the tubes from being lifted off the supports.