Bormax prima with exchangeable centre point and pre-drill bit. Two in reverse order staggered, grooved main cutting edges, a circumferencial cutting edge with longitudinal grooves - both effecting that a clear less feed force is necessary. Also they minimize the friction and the growth of heat. The pre-drill bit is ideal for drilling at an angle which is not 90° in workpieces surface, which occurs for example in the construction of staircase. Can be used with the centre point as traditional Bormax. Ø 16.2 mm for banisters with 16 mm stainless steel tubes.Clean drilling at many angles into soft wood, European hard wood, and MDF panels. Very good alternative to the expensive drill bit for construction of stairs product line 1575. In combination with extension shanks product line 1639 perfectly suitable for drilling deep holes. For harder materials like solid wood or plastic coated boards we recommend our product line 1664.