A: Hello- Unfortunately, the spring and steel ball are not available as replacement parts.
A: No, this is an 3/8 inch arbor hole saw. Mike
A: For a hole saw that big you need a large drill with an extra side handle
A: HI Dave, the shank type for this pilot bit is a hex. It doesn't require the use of an adapter and its universal fit is compatible with all hole saw brands.
A: Hi Dave, you can find the pilot bit with the following link- https://www.milwaukeetool.com/Products/Accessories/Hole-Saws/Hole-Saw-Arbors-and-Pilot-Bits/49-56-7110. The carbide teeth hole saws provide the longest life in general purpose and extreme materials with the ability to cut through stainless steel, cast iron, fastener embedded wood, cement board, fiberglass, plaster, asphalt shingles, and more with ease.