Bench drilling machine, referred to as bench drill for short, is a kind of small hole drilling machine with simple operation, which is usually installed on a special workbench. The drilling diameter of bench drill is generally below 13mm, and the maximum is not more than 25mm. Spindle speed change is generally realized by changing the position of V-belt on the tower pulley, and spindle feed is manually operated. The speed-changing part directly uses pulleys to change speed, so the speed is relatively high, and the general minimum speed is above 400r/min. For materials with large aperture and high hardness, it is not suitable for low-speed machining of workpieces.
For example, when the minimum rotation speed is 400r/min, when drilling a hole with a diameter greater than 13mm on 45 # steel, it is best to drill a small hole first, and then use a drill to enlarge the hole. When processing, use emulsion to cool the drill bit in time.