IRWIN Speedbor Max Wood 3-piece Boring Bit Set

I bought these bits originally to bore holes through some ¾ inch hardwood.The bits drill quick, clean holes and make a much cleaner cut when you bore through the other side. It’s not as clean as hole saw, but it’s a lot better than the tear out you see when you use a spade bit. It was when I started using these bits for reno projects that I ran into problems 1. I figured the bits would make quick work of drilling holes through 2x4 joists for laying conduit, but I found the bits would bog down about inch into the wood. Turns out the self-feeding screw tip will rapidly draw the bit into contact with the material and stall the drill. I found this to be a big problem in wood with knots. If you have a really powerful corded drill or a cordless impact driver (which is what I used to finish the job), then you can enough torque to keep these bits turning, but even an 18V drill will stall. 2. Even a small brad nail will wreck these bits. The tips on these bits aren’t low quality, but if they hit a nail it will gouge the cutting blades. I haven’t been able to find a way to file out the damage. (A Drill Doctor doesn’t work with this speedbor design.) This led to pick up some good quality DeWalt spade bits (#54-0637-8) for doing rough work like building a deck. They work great, don’t bog down if you use a regular drill, and can be easily sharpened if they take damage from a nail. I can’t say that the Speedbor bits are a bad product. They work well, but they can damaged so easily that I find they are only useful in a wood shop, not a reno project or work site.

These drill bits chew through wood like you would not believe, fast with very little effort. I highly recommend