The NailMaid. The safe and comfortable way to cut your fingernails. Apparently. Rechargeable, 6000 RPM abrasive rotary discs, slots for the nails. Doubles up as a celery slicer. Nah, just kidding. Around $60.00.
Nail length is determined by slot positioning. The nearer to the centre of the contour plate you go the less your nail will be filed and vice versa. Select the slot that best fits your finger shape and size. Take care to ensure that the skin of the finger does not go into the slot. Press the switch to start operating. Now pivot your finger slowly from side to side and gradually increase the pressure so that the fingernail goes deeper into the slot and is gradually shortened more and more. When your fingernail is no longer affected by the grinding wheel you can move to the next slot and repeat the process to shorten nails further or stop if happy with the length.