Symmetric cutting tool including cutting blade and tool holder provided with converging abutment surfaces

A tool holder (100, 100′, 100″) extending along a holder longitudinal axis (H) defining opposite forward and rearward holder directions (Fh, Rh);

• the tool holder (100, 100′, 100″) having a holder symmetry plane (Sh2) containing the holder longitudinal axis (H);
• the tool holder (100, 100′, 100″) comprising:
• opposing upper and lower holder surfaces (102, 104) extending along, and on opposite sides of the holder symmetry plane (Sh2);
• opposing first and second side holder surfaces (106, 108) extending along the holder longitudinal axis (H) and connecting the upper and lower holder surfaces (102, 104);
• a front holder surface (110) connecting the upper and lower holder surfaces (102, 104) and the first and second side holder surfaces (106, 108);
• and
• a blade pocket (120) recessed in the first side holder surface (106) and opening out to the front holder surface (110);
• the blade pocket (120) comprising:
• a pocket base abutment surface (122) transverse to the holder symmetry plane (Sh2);
• a first holder bore (124a) opening out to the pocket base abutment surface (122);
• and
• a pocket peripheral surface (128) extending from the pocket base abutment surface (122) towards the first side holder surface (106) and comprising:
• first and second pocket abutment walls (130a, 130b) located on opposite sides of the holder symmetry plane (Sh2) and converging in the rearward holder direction (Rh) at a first holder taper angle (γ1);
• wherein
• the first and second pocket abutment walls (130a, 130b) exhibit a mirror symmetric angle about the holder symmetry plane (Sh2), with the first holder taper angle (γ1) satisfying the following condition:
• 25°≤y1≤40°;
• and
• the upper and lower holder surfaces (102, 104) exhibit a mirror symmetric angle about the holder symmetry plane (Sh2).

A cutting tool (1, 1′, 1″) comprising:

• a tool holder (100, 100′, 100″) extending along a holder longitudinal axis (H) defining opposite forward and rearward holder directions (Fh, Rh), the tool holder having a holder symmetry plane (Sh2) containing the holder longitudinal axis (H), the tool holder comprising:
• opposing upper and lower holder surfaces (102, 104) extending along, and on opposite sides of the holder symmetry plane (Sh2);
• opposing first and second side holder surfaces (106, 108) extending along the holder longitudinal axis (H) and connecting the upper and lower holder surfaces (102, 104);
• a front holder surface (110) connecting the upper and lower holder surfaces (102, 104) and the first and second side holder surfaces (106, 108);
• and
• a blade pocket (120) recessed in the first side holder surface (106) and opening out to the front holder surface (110);
• the blade pocket (120) comprising:
• a pocket base abutment surface (122) transverse to the holder symmetry plane (Sh2);
• a first holder bore (124a) opening out to the pocket base abutment surface (122);
• and
• a pocket peripheral surface (128) extending from the pocket base abutment surface (122) towards the first side holder surface (106) and comprising:
• first and second pocket abutment walls (130a, 130b) located on opposite sides of the holder symmetry plane (Sh2) and converging in the rearward holder direction (Rh);
• wherein
• the first and second pocket abutment walls (130a, 130b) exhibit a mirror symmetric angle about the holder symmetry plane (Sh2);
• and
• the upper and lower holder surfaces (102, 104) exhibit a mirror symmetric angle about the holder symmetry plane (Sh2);
• a cutting blade (20, 20′, 20″) extending along a central blade axis (L) defining opposite forward and rearward blade directions (Fb, Rb), the cutting blade having first and second symmetry planes (S1, S2) perpendicular to one another, each containing the central blade axis (L), the cutting blade comprising:
• opposite first and second blade side surfaces (22, 24) extending along, and on opposite sides of, the first symmetry plane (S1);
• a blade peripheral surface (30) connecting the first and second blade side surfaces (22, 24);
• a blade cutting portion (50) comprising a first insert seat (62);
• and
• a blade fastening portion (70) extending from the blade cutting portion (50) in the rearward blade direction (Rb);
• the blade peripheral surface (30) comprising:
• opposite top and bottom blade surfaces (32, 34) extending along, and on opposite sides of, the second symmetry plane (S2);
• a forwardly facing forward blade surface (36) extending between the top and bottom blade surfaces (32, 34);
• and
• a rearward blade end (42) opposite the forward blade surface (36);
• at the blade fastening portion (70):
• the top blade surface (32) comprises a first peripheral blade abutment sub-surface (80a);
• the bottom blade surface (34) comprises a second peripheral blade abutment sub-surface (80b);
• the first and second blade side surfaces (22, 24) comprise, respectively, first and second blade side abutment sub-surfaces (82, 84);
• and
• a first blade bore (72a) opens out to the first and second blade side abutment sub-surfaces (82, 84);
• wherein:
• the first and second peripheral blade abutment sub-surfaces (80a, 80b) converge in the rearward blade direction (Rb) at a first taper angle β1 and exhibit a mirror symmetric angle about the first and second symmetry planes (S1, S2);
• a fastening member (144);
• and
• a cutting insert (60) releasably secured to the first insert seat (62) of the cutting blade (20, 20′, 20″);
• wherein:
• the cutting blade (20, 20′, 20″) is releasably secured to the tool holder (100, 100′, 100″) by the fastening member (144) passing through the first blade bore (72a) and engaging the first holder bore (124a);
• the mirror symmetric angles of the cutting blade (20, 20′, 20″) and the tool holder (100, 100′, 100″) are configured to facilitate the cutting blade (20, 20′, 20″) to be secured to the tool holder (100, 100′, 100″) in both of the following two configurations, namely:
• a first configuration where the second blade side abutment sub-surface (84) abuts the pocket base abutment surface (122) and the first and second peripheral blade abutment sub-surfaces (80a, 80b) respectively abut the first and second pocket abutment walls (130a, 130b);
• and
• a second configuration where the first blade side abutment sub-surface (82) abuts the pocket base abutment surface (122) and the first and second peripheral blade abutment sub-surfaces (80a, 80b) respectively abut the second and first pocket abutment walls (130b, 130a).