T-slot cutter

1. A T-slot cutter for machining a T-shaped groove in a workpiece, the T-slot cutter, comprising:

a cylindrical body;

a disc-shaped insert portion; and

a fixing device that detachably fixes the insert portion to one end portion in an axial direction of the body, wherein

the insert portion can be configured by a single disc-shaped insert or by a plurality of the inserts coaxially overlaid with each other, the insert including blade portions on an outer peripheral edge portion of the insert,

the insert, on each of both faces, comprises:

convex portions respectively protruding from a center in a thickness direction of the insert to both sides in the thickness direction, the convex portions being most separated from the center; and

concave portions provided in sections excluding the convex portions, the concave portions respectively protruding from the center to the both sides in the thickness direction, and the concave portions being lower than the convex portions, and

when the plurality of the inserts are coaxially overlaid with each other, on each of mating faces of all the inserts that are overlaid with each other, convex portions provided on a mating face of a first insert are inserted in a concave portions provided in a mating face of a second insert, and the convex portions provided on the mating face of the second insert are inserted in the concave portions provided in the mating face of the first insert, the first insert being one insert of adjacent two of the inserts, and the second insert being another insert of the adjacent two of the inserts.

2. The T-slot cutter according to claim 1 , wherein

the convex portions are provided between the blade portions and a center portion of the insert.

3. The T-slot cutter according to claim 1 , wherein

a shaft hole is provided in the center portion of the insert, the shaft hole penetrating in the thickness direction,

a contact face is provided on the one end portion of the body, the contact face being in contact with one face of the insert, and

a boss is provided in a center portion of the contact face, the boss protruding along the axial direction of the body, and the boss being inserted in the shaft hole.

4. The T-slot cutter according to claim 3 , wherein

the contact face, comprises:

body side convex portions protruding to the one face side in positions corresponding to the concave portions provided in the one face, the body side convex portions being inserted in the concave portions; and

body side concave portions provided to be lower than the body side convex portions in positions corresponding to the convex portions provided on the one face, the convex portions being inserted in the body side concave portions.

5. The T-slot cutter according to claim 4 , wherein

the fixing device is a screw,

an insertion hole is provided in the insert, the insertion hole penetrating in the thickness direction, and a shaft portion of the screw being to be inserted in the insertion hole, and

a screw hole is provided in the contact face in a position corresponding to the insertion hole, the screw being to be tightened in the screw hole.

6. The T-slot cutter according to claim 1 , wherein

leading end portions of the convex portions provided on the mating face of the first insert are in contact with bottom portions of the concave portions provided in the mating face of the second insert, and

leading end portions of the convex portions provided on the mating face of the second insert are not in contact with bottom portions of the concave portions provided in the mating face of the first insert.

7. The T-slot cutter according to claim 1 , wherein

on each of the both faces of the insert,

the number of the convex portions and the number of the concave portions are the same number n, and

when a minimum angle indicated by two first virtual straight lines when the two first virtual straight lines from the center portion of the insert contact outermost peripheral edge portions of the convex portion and include a whole of the convex portion between the two first virtual straight lines is X, and a maximum angle between two second virtual straight lines when the two second virtual straight lines from the center portion contact outermost peripheral edge portions of the concave portion and do not include the convex portion between the two second virtual straight lines is Y, then:

X is less than Y,

a sum of Xs of then number of convex portions is less than 180°,

a sum of Ys of the n number of concave portions is greater than 180°,

among Xs of the n number of convex portions, a maximum angle X max is less than 180/n°, and

among Ys of the n number of concave portions, a maximum angle Y max is greater than 180/n°.

8. The T-slot cutter according to claim 1 , wherein

when the insert portion is configured by coaxially overlaying the plurality of the inserts with each other, a width of the groove cut into the workpiece by the blade portions provided on each of the plurality of the inserts is adjustable by replacing one of the plurality of the inserts with the insert having a different thickness.

9. The T-slot cutter according to claim 1 , wherein

the insert portion comprises:

the first insert and the second insert; and

a third insert, the third insert being the insert overlaid between the first insert and the second insert, and

a groove width is adjustable by changing a thickness of the third insert, the groove width being a length parallel to the axial direction of the groove cut into the workpiece.

10. The T-slot cutter according to claim 1 , further comprising:

a plate-shaped spacer overlaid between the mating face of the first insert and the mating face of the second insert when the plurality of the inserts are coaxially overlaid with each other.

11. The T-slot cutter according to claim 10 , wherein

the spacer is arranged between the convex portions provided on the mating face of the first insert and the bottom portions of the concave portions provided in the mating face of the second insert that are in contact with the leading end portions of the convex portions.