3/4" Straight Shank #2 Jacobs Taper Chuck Arbor Quantity:1 and the rounded square shape

and the rounded square shape fits comfortably in your palm

Counterboring is the enlargement of a portion of a hole that has previously been formed

Part Number D/ACOS

Drill Bit Size: 16

Part Number BRCT342

3/4" Straight Shank #2 Jacobs Taper Chuck Arbor Quantity:1 and the rounded square shapeProduct Description Drill chuck arbors are adapters used to mount drill chucks onto machine spindles or tailstocks. They provide a secure and precise connection between the drill chuck and the machine, ensuring accurate drilling operations. Drill chuck arbors are essential for accommodating various drill chuck sizes and machine interfaces in machining applications. Brand Drill America Part Number DEWA4202