There was a need to drill large holes without boring. The holes were made in large sheets of metal, the dimensions of which would not allow the part to be clamped into the lathe. Having studied the ballerina shoes offered by Chinese manufacturers, I decided not to buy a ready-made one, not to wait, but to make my own.
Several hours were spent on the work (including filming) and about an hour on selecting the necessary sharpening of the cutter. The result is a fairly rigid tool that can be used to drill holes up to 100mm in diameter or even larger. In this case, an autonomous VFG on an Russian milling NGF 110 with direct drive is used and there is not enough torque at low speeds for drilling large diameters. But the ballerina coped with the planned tasks easily.
In the process, it turned out that with the correct selection of cutting modes, there is no crushing and noise that can be heard when drilling with Chinese ballerinas on drilling machines.
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