"These self feed bits by Milwaukee Tools are no joke.
They bore big holes quickly into wood framing members. The typical homeowner may never need anything like these. They can be pricey.
Many Electricians and Plumbers rely on Milwaukee's Selfeed Bits for large hole drilling in wood. The inside cutting plane shaves the hole radius for clean smooth holes without pressure. A removable, replaceable feed screw draws the bit into the gummiest of woods effortlessly. A 7/16 In. hex shank provides a secure gripping surface for a 1/2 inch drill chuck.(these bits will not fit in a 3/8ths drill chuck.) These bits feature
Removable and replaceable feed screws, and cutting edges that can be resharpened.
These bits require a 1/2 inch drill that has the power to turn them, Typically, at a low RPM. I recommend a corded 1/2 inch drill with a side handle. Both my milwaukee right angle drill and my milwaukee straight 1/2 inch can spin these, while my Black and Decker hammer drill cannot. (see my reviews on these) Most manufacturers will list the capacities of their drills in different materials, so you might want to check to see if your drill can handle these before buying. (If your drill is a Milwaukee, you are probably safe here)
Reasons for buying a bit like this? For drilling holes over 1&1/2 inches, it is either this or a hole saw.
I hate holesaws because I have to stop and remove the waste material out from the inside of the saw after each hole.
I have 3 of these bits that I use for plumbing projects- 1&3/4, 2", and 2&9/16. Most residential drain lines(except toilets) are 1&1/2 or 2''. I recently used my 2&9/16 self feed to bore through some framing to feed a 2 inch pipe for venting a slop sink in my pantry.
When using these bits, think safety- Use a drill that has a aux. handle and brace the drill in such a way that if the bit gets stuck, and the drill doesn't, that you are not going to get slammed or pinned!
These bits are available in sizes from 1 inch to 4&5/8ths."
What is your level of technical expertise? Professional