Tube length for special drills Please use the guide below to calculate the drill tube length. Workpiece Guide bush Double tube connector Drill head Outer tube Bar rest Inner tube L5 L1 L2' L3 L2'' L4 Lo (OAL Outer) L6 Li (OAL Inner) Lo = Outer tube overall length Outer tube overall length Lo 㲈 L1 + L2 + L3 + L4 - L5 Li = Inner tube overall length L1 = Guide bush length (or pilot hole depth)L2=Drilling depth (L2' + L2")Inner tube overall length Li = Lo + L6 L3 = Bar rest length L4 = Length of outer tube in connector* DTC L4* L6** L5 = Length from drill tube tip and peripheral DTC 4R (OT00 - OT13) 120 30 edge tip DTC 5R (OT14 - OT20) 0 190 L6 = Difference between outer tube length and DTC 6R (OT212 - OT25) 0 220 inner tube length** (mm) For smooth drill entry, make sure that the drill head is inside the guide bushing (or pilot hole) all the way up to 5 mm over the outer tube. DCN-DCX L5 DCN-DCX L5 DCN-DCX L5 18.4 - 20 31.5 25 - 26.4 40 38 - 43 45 20.01 - 21.8 33.5 26.41 - 31 42 43.01 - 47 55 21.81 - 21.99 33.5 31.01 - 33.3 47 47.01 - 51.7 51 22 - 24.1 35.5 33.31 - 36.2 50 51.71 - 56.2 56 24.11 - 25 35.5 36.21 - 39.6 55 56.21 - 65 66 25.01 - 26.4 37.5 39.61 - 47 60 65 - 79.99 75 26.41 - 28 37.5 47.01 - 51.7 66 80 - 111.99 83 51.71 - 65 71 112 - 147.99 87 148 - 183.99 86 Tungaloy 067