Cobalt containing special stainless steel drill bit, 4mm angle, do not move?
No matter what drill, the head must be sharpened! The small drill can be struck because the front edge is well sharpened! And 8.5 of the drill bit can not drill through, because the drilling side of the two cutting edges did not grind out (front angle is lower than the back angle, resulting in non cutting! To grind to the rear corner, lower than the front corner!!!!!!!!. When the drill bit blade grinding, drilling 4mm angle, is very fast, also don't add coolant! (head color change, drill when there is a cry, two sides do not chip out, all the drill bit did not wear well), grinding drill bit is a learning, learning is not difficult. Learn to grind the drill bit and drill around with the 10mm to see the edges.
The characteristics of stainless steel is high toughness, easy to stick a knife. So the drill hardness is high, surface finish better than ordinary bits, the bit angle large (130--135 degrees). At the same time to the full amount of feed and cooling. More than 0.15mm as much as possible without cutting in cold hardened layer. The cutting speed is as low as possible to reduce the cutting temperature. The cutting fluid is made of concentrated emulsions. Commonly used stainless steel drills are: high cobalt bit (M35 bit, M42 bit), in which the M42 bit is the most cost-effective, and carbide drills are also available.
What drill, what power, what speed?.Iron and steel complex, hard harder than stainless steel.The drill is to be sharpened.
