A cutting tool holder that supports a cutting insert including a rake face, a flank face continuous to the rake face, and a cutting edge constituted of a ridgeline that defines a boundary between the rake face and the flank face, the cutting tool holder comprising:
- a holder body having a seat face on which the cutting insert is placed;
- a pressing member that positions and fixes, to the holder body, the cutting insert placed on the seat face;
- and
- a fastener that fixes the pressing member to the holder body,
- wherein
- the pressing member has a front end portion and a base end portion, the front end portion being closer to the cutting edge of the cutting insert placed on the seat face than the base end portion, the base end portion having a base end surface, a perimeter of the base end surface has an elliptical shape,
- the front end portion is provided with a first coolant ejection hole via which coolant is ejected,
- a first flow path through which the coolant flows is provided inside the holder body,
- a coolant reservoir and a second flow path are provided inside the pressing member, the coolant reservoir is connected, via the non-circular coolant inlet hole, to the first flow path when the pressing member is fixed to the holder body, and the second flow path supplies, to the first coolant ejection hole, the coolant from the first flow path and the coolant reservoir, the coolant reservoir intersects the base end surface,
- in respective cross sections orthogonal to a flow direction of the coolant, the coolant reservoir has a cross sectional area, the first flow path has a cross sectional area, and the second flow path has a cross sectional area, the cross sectional area of the coolant reservoir is larger than the cross sectional area of the first flow path, the cross sectional area of the coolant reservoir is larger than the cross sectional area of the second flow path,
- an entirety of the coolant reservoir is disposed at a position closer to the base end surface than a center longitudinal axis of the fastener, in a direction from the front end portion toward the base end portion,
- the flow direction of the coolant in the coolant reservoir is inclined relative to the center longitudinal axis of the fastener,
- in a plan view of the pressing member, the entirety of the coolant reservoir and an entirety of the second flow path are on an opposite side of an imaginary straight line than the fastener, the imaginary straight line is parallel to the direction from the front end portion toward the base end portion, the imaginary straight line extends from the front end portion to the base end surface,
- the pressing member has a through-hole through which the fastener passes,
- in the plan view of the pressing member, the through-hole has an elliptical shape, and
- in the plan view of the pressing member, a major axis of the through-hole is parallel to the direction from the front end portion toward the base end portion.