The standard tolerance of boreholes is IT10 ~ IT11, and the surface roughness is Ra50 ~ ra12.5. It can only process holes with low requirements or rough processing as holes. Drilling operations are usually carried out on rigs, sometimes by hand. Commonly used drilling tools are:

　　手電鉆和手風鉆。這是一種由電力和壓縮空氣分別驅動的手持鉆具。它的進食是靠人的推力完成的。具有轉速高、鉆速快、使用輕便等特點。使用手鉆時應注意安全，如接線應完好，操作時應戴絕緣手套。氣動手鉆以壓縮空氣為動力，相對安全，但成本較高。

　　Electric drill and pneumatic drill. This is a hand-held drilling tool driven by electric power and compressed air respectively. Its feeding is done by human thrust. It has the characteristics of high speed, fast drilling speed and light use. When using the hand drill, attention should be paid to safety. If the wiring should be intact, insulating gloves should be worn when operating. Pneumatic hand drill is driven by compressed air, which is relatively safe, but the cost is high.

　　(2)臺鉆和立式鉆。臺鉆有很多種類型，但其結構和工作原理基本相同，都是由電機帶動鉆頭旋轉完成切削動作，并由進給手柄控制進給。立式鉆床有很多種，如z525b型立式鉆床。鉆孔大直徑5mm，主軸有六種轉速，可手動或自動進給刀具。

　　(2) Bench drill and vertical drill. There are many types of bench drills, but their structure and working principle are basically the same. They are all driven by motor to complete the cutting action and controlled by feed handle. There are many kinds of vertical drilling machine, such as Z525b vertical drilling machine. The maximum diameter of drilling hole is 5mm, and the spindle has six rotational speeds. The tool can be fed manually or automatically.

　　搖臂鉆床。搖臂鉆床結構復雜，自動化程度高，使用范圍廣。國產Z35搖臂鉆床大直徑為50mm。搖臂上可移動搖臂上的搖臂主軸箱，搖臂可繞主軸柱軸線旋轉，并沿主軸柱上下移動。橫臂的位置由制動裝置固定。因此，在允許的橫臂長度范圍內，立軸可以對準工件的任何位置。

　　Radial drilling machine. Rocker drilling machine has complex structure, high automation and wide application range. The maximum diameter of domestic Z35 rocker drilling machine is 50mm. The rocker arm spindle box on the rocker arm can be movable on the rocker arm. The rocker arm can rotate around the axis of the spindle column and move up and down along the spindle column. The position of the arm is fixed by the brake device. Therefore, within the allowable arm length range, the vertical axis can be aligned to any position of the workpiece.

　　(4)標準麻花鉆頭。鉆井主工具對鉆井質量有重要影響。

　　(4) Standard twist drills. Drilling main tools have an important influence on drilling quality.

　　濟南哪里有寶馬汽車維修的就找陸通汽修，更多有關汽修的小知識可點擊官網咨詢：http://www.yiyili.com/

　　Where there is BMW repair in Jinan, you can find Lu Tong Auto Repair. For more information about auto repair, please click on the official website: http://www.yiyili.com./