The design consists of the visual features of the entire drill set case as shown in the drawings.Drawings of the design are included.Fig. 1 is a front perspective view of a first variant of the drill set case.Fig. 2 is a rear perspective view of the first variant of the drill set case in an extended position.Fig. 3 is a top view of the first variant.Fig. 4 is a side view of the first variant.Fig. 5 is a front view of the first variant.Fig. 6 is a rear view of the first variant.Fig. 7 is a side view of the first variant.Fig. 8 is a bottom view of the first variant.Fig. 9 is a front perspective view of the first variant with the drill set case open.Fig. 10 is a rear perspective view of the first variant with the drill set case open.Fig. 11 is a top view of the first variant with the drill set case open.Fig. 12 is a front view of the first variant with the drill set case open.Fig. 13 is a rear view of the first variant with the drill set case open.Fig. 14 is a left hand side view of the first variant with the drill set case open.Fig. 15 is a front perspective of a second variant of a drill set case.Fig. 16 is a rear perspective of the second variant of the drill set case.Fig. 17 is a top view of the second variant.Fig. 18 is a right hand side view of the second variant.Fig. 19 is a front view of the second variant.Fig. 20 is a left hand side view of the second variant.Fig. 21 is a rear view of the second variant.Fig. 22 is a bottom view of the second variant.Fig. 23 is a front perspective of a third variant of a drill set case.Fig. 24 is a rear perspective of the third variant of the drill set case.Fig. 25 is a top view of the third variant.Fig. 26 is a right hand side view of the third variant.Fig. 27 is a front view of the third variant.Fig. 28 is a rear view of the third variant.Fig. 29 is a left hand side view of the third variant.Fig. 30 is a bottom view of the third variant.Fig. 31 is a front perspective of a fourth variant of a drill set case.Fig. 32 is a top view of the fourth variant.Fig. 33 is a right hand side view of the fourth variant.Fig. 34 is a front view of the fourth variant.Fig. 35 is a rear view of the fourth variant.Fig. 36 is a left hand side view of the fourth variant.Fig. 37 is a bottom view of the fourth variant.Fig. 38 is a front perspective view of the fourth variant with the drill set case open.Fig. 39 is a rear perspective view of the fourth variant with the drill set case open.Fig. 40 is a top view of the fourth variant with the drill set case open.Fig. 41 is a front view of the fourth variant with the drill set case open.Fig. 42 is a rear view of the fourth variant with the drill set case open.Fig. 43 is a left hand side view of the fourth variant with the drill set case open.Fig. 44 is a front perspective view of the second variant with the drill set case open.Fig. 45 is a rear perspective view of the second variant with the drill set case open.Fig. 46 is a top view of the second variant with the drill set case open.Fig. 47 is a front view of the second variant with the drill set case open.Fig. 48 is a rear view of the second variant with the drill set case open.Fig. 49 is a left hand side view of the second variant with the drill set case open.Fig. 50 is a front perspective view of the third variant with the drill set case open.Fig. 51 is a rear perspective view of the third variant with the drill set case open.Fig. 52 is a top view of the third variant with the drill set case open.Fig. 53 is a front view of the third variant with the drill set case open.Fig. 54 is a rear view of the third variant with the drill set case open.Fig. 55 is a left hand side view of the third variant with the drill set case open.