P: Lever-lock clamping system. It pulls the insert back into the pocket securely via an internal lever mechanism, offering completely flat, obstruction-free clearance on top of the tool.
S: Square insert shape shape (uses double-sided SNMG or SNMA negative inserts).
B: 75-degree approach angle (lead angle) designed for heavy longitudinal turning and face chamfering.
N: Negative 0-degree insert normal rake angle (providing high edge strength for tough roughing cuts).
L: Left-hand cutting direction.
📏 Comparing the Two Sizes
The numbers following the main geometry designation dictate the physical dimensions of the square steel shank:
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PSBNL 4040 (Heavy Duty)
PSBNL 2525 (Standard)
Shank Height & Width
40 mm × 40 mm square
Shank Height & Width
25 mm × 25 mm square
Overall Length (OAL)
250 mm (Designated by S)
Overall Length (OAL)
150 mm (Designated by M)
Typical Insert Pocket
Optimized for massive SNMG 1906 or SNMG 2507 inserts
Typical Insert Pocket
Optimized for standard SNMG 1204 or SNMG 1506 inserts
Machine Type
Large-scale heavy CNC lathes / Roughing VTLs
Machine Type
Mid-sized standard CNC lathes