To enhance processing accuracy in a boring device retaining a lengthy tool at a spindle.
The boring device 11 processes an inner peripheral surface of a through hole 35 formed on a work W by relatively moving a table 27 provided on a bed 13 and having the work placed thereon and the spindle 23 retaining and rotating one end of the lengthy tool T. The other end or a midway part of the tool T is supported by a cylindrical support surface 31 of a support fixture 29 provided on the bed 13 or the table 27. A fluid bearing is formed between the support surface 31 and an outer peripheral surface of the tool T by feeding a fluid to the support surface 31 through the support fixture 29. The tool T is supported by the cylindrical support surfaces of the two support fixtures disposed at both sides of the work W. The spindle 23 and the tool T may be connected through a coupling for transmitting rotation of the spindle to the tool T in the state where a center axis of the tool T is deviated from a rotation axis of the spindle 23.
Jun Tsuruta
Tetsuro Shimada
Masaya Nishiyama
Higuchi Souji