Homedepot offers DEWALT 7/16 in. Shank Quick Change Mandrel Fits Hole Saws 1-1/4 in. - 6 in.-DW1803 for $8.06 with free store pickup.

Product Description:
DEWALT offers a full range of standard and quick change mandrels for versatility in a wide range of hole saws. DEWALT bi-metal hole saws are among the fastest-cutting, longest-lasting hole saws available anywhere. Each has a double-tooth design and sharper tooth geometry to cut faster and cleaner through a variety of jobsite materials, including wood, metal and plastics. Its extra-thick, hardened backing plate prevents thread stripping, and the deep-cut design easily saws through 2-by lumber in a single pass.

• Spring-loaded collar that automatically engages drive pins to prevent hole saws from locking to the mandrel
• For use with 1-1/4 in. - 6 in. hole saws
• Features double set screws with a recessed combination head for quick and easy centering bit changes
• Quick change mandrels utilize hardened steel construction and have been tested through 15,000 plus cycles to deliver jobsite durability
• Pilot bits feature the patented DEWALT pilot point tip for faster material penetration, particularly in metal

Thanks Maggie