| 摘要 |
<p>An expanded hole drilling device capable of expanding the diameter of a pre-drilled hole to a large diameter without causing decentering, a component for the expanded hole drilling device, and an expanded hole drilling method. The expanded hole drilling device (10) comprises a drill holder (22) fitted to a drill holding part (18) in place of a drill (16) and holding the drill (16) and a centering attachment (24) fitted to the drill holder (22) and formed in a conical shape at its tip part. The expanded hole drilling method comprises a step for displaceably disposing a drilled work on a table (14), a step for inserting the tip part of the centering attachment (24) into the drilled hole and centering them with each other, a step for fixing the centered work to the table (14), and a step for drilling the work to expand the hole with the drill (16) after dismounting the centering attachment (24).</p> |
