ISO toolholders: reading the code

How to read a toolholder code

Take PCLNR 2525M12. P is the lever lock through the insert hole, C the insert shape (80° rhombic), L the style, i.e. a 95° cutting edge angle, N the insert clearance (0°, negative insert), R the hand, right. Then 2525 is the 25 × 25 mm shank, M the length, 150 mm, and 12 the insert size: the holder takes a CNMG or CNMA 1204.

The code follows ISO 5608 and is the same for every maker. After the insert size a maker may add letters of its own, for instance for internal coolant: read those in its catalogue.

Insert clamping

• P, lever: pulls the insert into the pocket through the hole. The most common system for negative inserts.
• D, rigid clamp: clamp and pin together, for heavy roughing and interrupted cuts.
• M: top clamp and pin in the hole.
• C: top clamp only, for inserts without a hole.
• S, screw: for positive inserts with a countersunk hole, like CCMT and DCMT. Compact, and it leaves the chip free.

The cutting edge angle

The third letter gives the angle at which the edge meets the workpiece (κr). L (95°) turns and faces with one tool; J (93°) copies profiles and gets into shoulders; N (63°) and V (72.5°) copy in both directions; B and R (75°) rough with a better protected edge; D and S (45°) chamfer and rough. On boring bars U (93°) and Q (107.5°) are common, to work right down to the bottom of the bore.

Boring bars

Bars follow ISO 6261: S20S-SCLCR09 is a steel bar (S), 20 mm in diameter, 250 mm long (S); after the hyphen the letters are the same as on external holders. The minimum bore the bar can work in is not in the code: it is in the catalogue. Bars starting with A or E have an internal coolant hole.

The most common toolholders, one page each