Advanced bee-keepers often dispense with these, but they are useful to a beginner. The flat-headed shoenails are driven into each side of the top bar (4 to each frame), 1 1/2 in. from each end; the distance between the heads of the nails should be 1 7/16 in., so that the frames will be that distance apart from centre to centre, when hung in the hive; they are indicated in Fig. 614 by small circles on the line above e.