1. The guide hole
　　During nesting, you can use the guide sleeve can also be pre-processed pilot hole (annular groove) on the workpiece, whose role is to guide the drill nesting cut, not cut hole deflection and prevent the cutting fluid splash. So that when the lead drilling within the outer cutting edge is not the same, allowing the pilot hole is smaller than the outer diameter of the spindle core drill inner edge of the size 1-2mm, while the spindle facing down a large chamfer 5x30o order to cut time easy introduction. Pilot hole diameter tolerance H9 can choose the surface roughness Ro of 3.2μm, the depth in the 20-80mm.
2. supporting sleeve
　　In order to strengthen the supporting role of core drill can drill and drill in nesting coupling member and then a piece of wood, nylon block or bakelite production support units, from the outer diameter is larger than the outer diameter of the drill nesting (2 / 1000- 4/1000) do (do a core drill diameter) hole in cutting is gradually entering its damping effect.
3. Selection of Cutting Parameters
　　Depending on the workpiece material. When using carbide core drill for hot rolling, normalizing, annealing, or the state of cold-drawn carbon steel or alloy steel, nitriding steel nesting When drilling, to cutting speed v is 80 ~ 120m / min, feed f was 0.12 ~ 0.2mm / r; when the swap quality steel nesting drilling, v is 60 ~ 110m / min, f is 0.15 ~ 0.18mm / r (the higher hardness to low); high-speed steel trepanning drilling process annealed steel, v is 30 ~ 50m / min.
4. Cited knife
　　The lead and retract that should prevent the blade to break something, especially in the processing aspect ratio larger than the hole 100, often due to the weight of the mandrel easily lead to sagging and retract. General can block the ends of the mandrel appliances, also available with an inner diameter of the mandrel and the workpiece diameter match, a width of 40-50mm wooden sets the mandrel hold, and then lead a knife, start cutting back on the wooden cover chopped You can continue processing.
　　Nesting machining the workpiece so that the general should not wear a jacket, especially the large diameter hole nesting and even more so, otherwise pull mandrels fall will damage the core drill drill. Bottom of the hole can still leave some solid length, until the workpiece is in turn turning to cutting core.
5. Coolant
　　When machining core drill hole, to use active mineral oil instead of emulsion or kerosene. Compared with deep-hole drilling, trepanning drilling required less pressure and flow is large. As depth increases hole is drilled nesting also need to increase pressure coolant flow.
6. The system of positional accuracy
　　In the core drill unprecedented, should adjust the position accuracy of each part of the system, the spindle, concentricity error between the guide sleeve and the drill pipe is not more than three 0.03mm, sets out the holes to prevent deflection