Square Hole Drill Bit Adapter with 4pcs Square Hole Drill Bit, Mortising Attachment for Drill Press, Mortise Machine, Power Tool Accessory for Drill Machines

【Square drill bit adapter】Fit for benchtop drill machine with hand drill clip diameters between 38 and 55mm (1.5 and 2.2 inches). 【Please Note】This adapter is not suitable for lithium battery drills and bench drills without round bore bearings. Suitable for old table drills and household table drills, please pay attention before ordering. 【Material】Square drill bit adapter is made of all-steel castings, which are strong and durable. If stored in a humid environment for a long time, it may cause some surface rust, which can be improved by simply wiping some protective oil. 【Drill bit diameter】1/4 Inch (6.4mm), 5/16 Inch (8mm), 3/8 Inch (9.5mm), 1/2 Inch (12.7mm). 【Easy to Drill】The carbide drill bit tipped is sharp and wear-resistant. With high hardness and long service life. The drill sleeve has a U-shaped design to facilitate the discharge of wood chips and improve the drilling efficiency.