What is needed to drill a hole? 

thanks for the comment and interest in the video. You probably meant 60 bar pressure when you said the calculation was incorrect. That value is calculated per the whole cross-sectional area of the bit, and thus poorly expressed, although correctly. From that number, you can perhaps deduce with what force the drill should be pressed towards the workpiece. The vertical force measurement is correct, I'm sure. When the cutting force is directed at the tip of the blade and the cutting edges, the question is how much force is needed at the cutting edge. After a quick internet search, structural steel ASTM A36, yield strength is 250 MPa and ultimate tensile strength 550 MPa (1MPa=10bar). From this we can conversely calculate, (assuming that in my drilling too the chips came off at a pressure of 550 MPA) that the width of the cutting surface is 0.15 mm with a 15 mm diameter bit and total downward force of 1200 N. I further assume that the force is directed to the extreme edge of the bit, because otherwise sharpening would hardly matter. So the actual cutting pressure may be much higher than 550 Mpa. It must be quite difficult to determine how the force is distributed near the edge of the bit. And I can't measure how wide or sharp the edge of the blade is either. Maybe I'll find out some way to numerically measure how sharp a drill bit is. My purpose was to show that the hobbyist must understand the most important requirements for tools, a sharp bit and the right amount of force needed for drilling. Numerical values, in my opinion, are more valuable than expressions like sharp or dull. All in all, I'm happy to learn by myself or with the advice of others how to drill that big hole. Learning the hard way by burning or breaking blades is frustrating and will bring your project to a halt. Thanks for the video link. ​

Hi, thanks for watching. Unhappy? Would you please tell the reason. I appreciate all feedback, just to make it better or correct errors.