while at the opposite end arms 12a and 12b terminate at an approximate 45 degree angle to the axis of arms 12a and 12b as is best seen in fig2 creating an angular surface 30 on each arm bores 28 could be used to attach another device 10 to the bottom of the first by the use of dowels or similar means thus providing an additional set of grooves 20 if the ceiling is to be suspended at a lower height than possible using device 10 fig4 illustrates the use of device 10 in the installation of the framework for use in hanging a suspended ceiling device 10 is secured to a ceiling joist 40 by locating joist 40 between arms 12a and 12b and adjusting clamp 26 by turning t handle 26b until joist 40 is firmly held between surface 26a and protrusions 22 a piece of gridwork 42 which is in the shape of an inverted t is positioned firmly within one of the pairs of grooves 20a 20b 20c or 20d located on arms 12a and 12b device 10 can also be used to install l shaped angle iron gridwork which is used along the walls when installing a suspended ceiling depending on the length of gridwork 42 it may be helpful to use a second device 10 attached to another joist 40 at some distance away from device 10 along the length of gridwork piece 42 gridwork piece 42 can then be accurately located at the proper distance from the floor by adjusting the position of device 10.