Such a great price. Was skeptical as they are half the price of one in store or all 20 but they work great! I had a mothers night where we made cake stands and 14 women made at least 4 holes plus 20 or so I have all done with just one of these exercises and it's still good to go!
Pros
Shaft Size(Approx.): 50 x 5.5mm / 2" x 0.2" (L*D); Overall length: 50 mm / 2 inches
This product is not intended but works perfectly. With a little guide I was able to drill the broken screw extractor out of the broken bolt I was dealing with. I couldn't be happier. It took about 17 of them to get through a bolt puller and it took a lot of fighting to make it. If you're on a roll, they can certainly get the job done. The build quality is pretty poor and I crushed a few of them by tightening the drill bit.
I used these drill bits to drill four holes in a 1.25 inch piece of granite. over the hole during the process to keep the bits as cool as possible. I needed an average of two bits per hole as the abrasive wears down the tip of the drill bit. I had two bits so be warned. The bits are hollow steel cylinders and the walls aren't very thick so if too hot or wedged slightly the cylinder will easily snap. Breakages are my fault as I probably didn't know what I was doing. I finished two incompleteβ¦