Today I watched a coworker of mine drilling a hole 2.25" diameter 11.5" deep in 4140 4.25" round.
Insert drill is a 5x Walter using through coolant on a 15" CNC Lathe. Not sure what speeds and feeds were used.
Very near the bottom of the hole, as flute length began to run out, rpms started dropping and the machine alarmed out before any e-stop could be applied. The drill spun in the tool pocket shearing set screws and it turned into a horrible mess. This is some kind of high strength, you only get 1 piece of stock, customer supplied material. It occurred to some of us that heating the material might set the drill free, but we were concerned about changing the material's properties/ annealing the drill etc.
Assuming The drill is still intact inside the work piece, how would you recommend it be removed?
This reminds me of "the sword and the stone"
Michael.
Insert drill is a 5x Walter using through coolant on a 15" CNC Lathe. Not sure what speeds and feeds were used.
Very near the bottom of the hole, as flute length began to run out, rpms started dropping and the machine alarmed out before any e-stop could be applied. The drill spun in the tool pocket shearing set screws and it turned into a horrible mess. This is some kind of high strength, you only get 1 piece of stock, customer supplied material. It occurred to some of us that heating the material might set the drill free, but we were concerned about changing the material's properties/ annealing the drill etc.
Assuming The drill is still intact inside the work piece, how would you recommend it be removed?
This reminds me of "the sword and the stone"
Michael.