Described herein is an orbital drilling system that includes an orbital drilling machine and a cutter. The orbital drilling machine includes a spindle and an eccentric rotation mechanism. The spindle is rotatable about a cutter axis. The eccentric rotation mechanism is coupled to the spindle and configured to orbit the spindle about an orbital axis, offset from the cutter axis. The cutter is co-rotatably coupled to the spindle and comprises a plurality of cutting edges, collectively defining a cutting diameter of the cutter. The cutting diameter of the cutter is adjustable.

An adzer bit includes a support member that defines a through hole that is configured to receive a fastener. The support member includes a cutting segment cap portion and a base portion. The support member also defines an annular slot that is axially disposed between the cutting segment cap portion and the base portion. A plurality of cutting segments are received and secured in the annular slot. The material of the plurality of cutting segments is harder than the material of the support member.

A rotary cutting tool includes a tool holder and a tool body releasably attached thereto. The tool body has a cutting portion that includes a peripheral insert pocket, for retaining a cutting insert. The tool holder includes an adjustment arrangement that includes a biasing member, movably attached to the tool holder, having a biasing portion. The cutting portion is adjustable between a non-flexed position and a flexed position. In the flexed position, the cutting portion is elastically deformed in a forward direction due to biasing engagement with the biasing portion, thereby adjusting the axial position of the insert pocket and thus the cutting insert.