Lathe Tooling Reference Guide | CNC Turning Tools & Inserts

Lathe Operations Overview

Understanding each operation helps you select the right tool geometry, insert grade, and cutting parameters.

Operation	Description	Common Tools	Key Considerations
Facing	Machining the end face of the workpiece perpendicular to the axis	PCLNR, MCLNR, DCLNR	Use 80° or 55° inserts; ensure clearance at center
OD Turning	Reducing the outside diameter along the length of the workpiece	PCLNR, MCLNR, DWLNR	Match insert angle to approach; consider chip flow
Roughing	High material removal rate with larger depth of cut	PCLNR, MWLNR	Use strong insert shapes (C, W, S); heavy chipbreakers
Finishing	Final pass for surface finish and dimensional accuracy	SVJBR, SDJCR	Small nose radius; light chipbreakers; higher speeds
Taper Turning	Creating a conical surface with varying diameter	PCLNR, MCLNR	Consider effective cutting angle; use appropriate clearance
Profiling	Complex contours combining radii, tapers, and steps	SVJBR, SDJCR, DVJNR	35° or 55° inserts for accessibility; check interference
Boring	Enlarging an existing hole from the inside	S-SCLCR, A-SDUCR	Minimize overhang; use anti-vibration bars for deep bores
Drilling	Creating a hole in the center of the workpiece	Center drills, indexable drills	Start with center drill; peck for deep holes
OD Threading	Cutting external threads on the workpiece	SER, SEL, Laydown	Match thread form (60° metric, 55° BSP); use thread relief
ID Threading	Cutting internal threads inside a bore	SIR, SNR	Ensure bore diameter allows tool entry; check clearance
Grooving	Cutting a narrow channel or recess	GFVR, DGFHR	Match insert width to groove; consider chip evacuation
Parting	Cutting off the workpiece from bar stock	QD, GY, Cut-off blades	Use narrow inserts; reduce speed near center; support part
Knurling	Creating a textured pattern for grip	Knurling tools	Match pitch to diameter; use cutting or forming style

Tool Holder Nomenclature

Tool holders follow standardized naming conventions that describe their clamping method, insert compatibility, and dimensions.

ISO Standard (Metric)

Example: PCLNR2525M12

P C L N R 25 25 M 12

P Clamping System

C Insert Shape

L Insert Clearance

N Tool Style

R Hand

25 Shank Height

25 Shank Width

M Tool Length

12 Insert IC

Position 1: Clamping System

Code	System	Description
`P`	Lever Lock	Most common; uses a lever to pull insert into pocket
`C`	Top Clamp	Clamp presses on top of insert; good for negative inserts
`S`	Screw	Center screw through insert; compact design
`M`	Multi-Lock	Combination of clamp and pin; very secure
`D`	Lever + Clamp	Dual locking for heavy machining

Position 2: Insert Shape

Code	Shape	Angle	Strength	Best For
`C`	Rhombus	80°	High	General turning, versatile
`D`	Rhombus	55°	Medium	Profiling, copy turning
`V`	Rhombus	35°	Low	Fine profiling, tight corners
`T`	Triangle	60°	Medium	General turning, 3 edges
`S`	Square	90°	High	Heavy roughing, 4/8 edges
`R`	Round	-	Highest	Heavy roughing, scaling
`W`	Trigon	80°	High	Heavy cuts, 6 edges

Position 3: Insert Clearance Angle

Code	Angle	Application
`N`	0°	Negative insert - double-sided, strong
`C`	7°	Standard positive clearance
`P`	11°	More positive - light cuts, profiling
`B`	5°	Slight clearance

Position 4: Tool Style (Approach Angle)

Code	Lead Angle	Application
`A`	90°	Square shoulder, facing
`B`	75°	General turning
`C`	75°	With offset (for facing)
`D`	45°	Heavy roughing
`F`	90°	End cutting, facing
`J`	93°	General with slight lead
`K`	75°	Standard OD turning
`L`	95°	Back-facing capable
`N`	63°	With offset
`R`	75°	Reduced lead
`S`	45°	Maximum chip thinning

Position 5: Hand of Tool

Code	Hand	Description
`R`	Right-hand	Cuts from right to left (toward chuck) - most common
`L`	Left-hand	Cuts from left to right (away from chuck)
`N`	Neutral	Can cut in both directions

Positions 6-9: Dimensions

Positions	Meaning	Example
6-7	Shank height (mm)	25 = 25mm height
8-9	Shank width (mm)	25 = 25mm width

Position 10: Tool Length

Code	Length Factor
`A`	Shortest
`D`	Short
`H`	Standard
`K`	Long
`M`	Medium (common)
`P`	Extra long

ANSI Standard (Inch)

Example: MCLNR-164D

M C L N R - 16 4 D

M Clamp Type

C Insert Shape

L Clearance

N Style

R Hand

16 Shank (1/16")

4 Insert IC

D Length

Tip: ANSI shank size is in 1/16" increments. So "16" = 16/16" = 1" square shank. The insert IC is also in 1/8" increments, so "4" = 4/8" = 1/2" IC.

Insert Nomenclature

Carbide inserts use a standardized code that defines shape, size, tolerance, and features.

ISO Standard

Example: CNMG120408-PM

C N M G 12 04 08 - PM

C Shape

N Clearance

M Tolerance

G Features

12 Size (IC)

04 Thickness

08 Corner R

PM Chipbreaker

Position 1: Insert Shape

Code	Shape	Included Angle	Edges	Strength
`C`	Rhombus	80°	2/4	Good balance of strength and accessibility
`D`	Rhombus	55°	2/4	Better accessibility, less strength
`V`	Rhombus	35°	2/4	Best accessibility, weakest
`T`	Triangle	60°	3/6	Good economy, medium strength
`S`	Square	90°	4/8	Strong, good for roughing
`R`	Round	-	Infinite	Strongest, for heavy roughing
`W`	Trigon	80°	3/6	Good economy and strength
`K`	Parallelogram	55°	2/4	For specific applications

Position 2: Clearance Angle

Code	Angle	Type	Application
`N`	0°	Negative	Double-sided, strongest, most economical
`A`	3°	Positive	Light cutting
`B`	5°	Positive	General positive
`C`	7°	Positive	Standard positive
`P`	11°	Positive	Heavy positive for aluminum/soft materials
`E`	20°	Positive	Extra positive for soft materials

Negative vs Positive: Negative inserts (N) are double-sided (twice the edges) and stronger but require more power. Positive inserts (C, P) cut more freely with lower forces but are single-sided.

Position 3: Tolerance Class

Code	IC Tolerance	Thickness Tolerance	Use
`M`	±0.08-0.18mm	±0.13mm	Standard machining
`G`	±0.025-0.08mm	±0.025mm	Precision finishing
`U`	±0.08-0.18mm	±0.13mm	Utility
`C`	±0.025mm	±0.025mm	Close tolerance

Position 4: Insert Features

Code	Feature
`A`	With hole, no chipbreaker
`G`	With hole, chipbreaker both sides
`M`	With hole, chipbreaker one side
`N`	No hole, no chipbreaker
`T`	With hole, chipbreaker one side, clearance
`W`	With hole, no chipbreaker, wiper

Positions 5-6: Insert Size (IC - Inscribed Circle)

Code	IC Diameter	Common Uses
`06`	6.35mm (1/4")	Small parts, finishing
`09`	9.525mm (3/8")	Light to medium machining
`12`	12.7mm (1/2")	General purpose - most common
`16`	15.875mm (5/8")	Heavy machining
`19`	19.05mm (3/4")	Heavy roughing
`25`	25.4mm (1")	Very heavy cuts

Positions 7-8: Thickness

Divide by 10 to get actual thickness in mm. Example: 04 = 4.76mm

Code	Thickness (mm)	Thickness (inch)
`01`	1.59mm	1/16"
`02`	2.38mm	3/32"
`03`	3.18mm	1/8"
`04`	4.76mm	3/16"
`05`	5.56mm	7/32"
`06`	6.35mm	1/4"

Positions 9-10: Corner Radius

Multiply by 0.1 to get actual radius in mm. Example: 08 = 0.8mm radius

Code	Radius (mm)	Radius (inch)	Application
`02`	0.2mm	0.008"	Fine finishing, weak edge
`04`	0.4mm	0.016"	Finishing
`08`	0.8mm	0.031"	General purpose
`12`	1.2mm	0.047"	Medium roughing
`16`	1.6mm	0.063"	Heavy roughing
`24`	2.4mm	0.094"	Very heavy roughing

Surface Finish Formula: Ra (μm) ≈ (feed² × 1000) / (8 × nose radius). Larger nose radius = better finish at same feed rate.

ANSI Standard

Example: CNMG-432

C N M G - 4 3 2

C Shape

N Clearance

M Tolerance

G Features

4 IC (1/8")

3 Thick (1/16")

2 Corner R

ANSI Size Codes

Position	Unit	Example
IC Size	1/8" increments	4 = 4/8" = 1/2" IC
Thickness	1/16" increments	3 = 3/16" thick
Corner Radius	1/64" increments	2 = 2/64" = 1/32" radius

Tool Types by Operation

Select the right tool holder style for your specific machining operation.

OD Turning - General

PCLNR - 80° insert, lever lock, versatile
MCLNR - 80° insert, top clamp
DCLNR - 55° insert, more access
DWLNR - 80° trigon, heavy cuts

OD Turning - Finishing

SVJBR - 35° insert, tight profiles
SDJCR - 55° insert, profiling
SVVCN - 35° insert, very accessible
SDUCR - 55° positive, light cuts

Facing

PCLNR/PCLNL - Standard facing
MWLNR - Heavy facing
SCLCR - Light facing

Boring Bars

S-SCLCR - Standard steel shank
S-SDUCR - 55° for profiles
A-SCLCR - Anti-vibration
E-SCLCR - Carbide shank
C-SCLCR - Coolant-through

Threading - External

SER - 60° external right-hand
SEL - 60° external left-hand
SER-NF - UN threads (55°)
Laydown style for rigidity

Threading - Internal

SIR - Internal right-hand
SNR - Internal neutral
Match bar diameter to bore
Consider chip evacuation

Grooving

GFVR - Face grooving
DGFHR - OD grooving
GY - Deep grooving
Match insert width to groove

Parting / Cut-off

QD - Quick disconnect blades
GY - Deep parting
Narrow inserts (2-3mm)
Reduce speed near center

Boring Bar Selection Guide

Bore Diameter	Bar Diameter	Max Overhang	Type
10-15mm	6-8mm	3×D	Steel
15-25mm	10-16mm	4×D	Steel
25-40mm	16-25mm	4×D	Steel or Carbide
40-60mm	25-40mm	5-6×D	Carbide or Anti-vib
>60mm	>40mm	6-10×D	Anti-vibration

Rule of Thumb: Use the largest possible boring bar diameter. Maximum overhang for steel is 4×D, carbide 6×D, anti-vibration 10×D.

Insert Grades & Coatings

Selecting the correct grade and coating is critical for tool life and productivity.

ISO Material Classification

Materials are grouped by their machining characteristics. Each group has recommended carbide grades.

ISO Code	Color	Material Group	Characteristics	Grade Range
P	Blue	Steel	Long chips, good machinability, adhesive wear	P10 - P40
M	Yellow	Stainless Steel	Work hardening, built-up edge, abrasive	M10 - M40
K	Red	Cast Iron	Short chips, abrasive, easy to machine	K10 - K40
N	Green	Non-ferrous	Soft, gummy, long chips, low forces	N10 - N30
S	Purple	Superalloys	High strength at temperature, work hardening	S10 - S30
H	Gray	Hardened Steel	>45 HRC, abrasive, high cutting forces	H10 - H30

Grade Number Guide: Lower numbers (P10, M10) = harder, more wear resistant, for finishing. Higher numbers (P40, M40) = tougher, for roughing and interrupted cuts.

Coating Types

Coating	Process	Max Temp	Color	Best Applications
TiN	PVD	600°C	Gold	General purpose, easy wear detection, low-alloy steel
TiCN	PVD/CVD	400°C	Gray-violet	Abrasive materials, cast iron, medium-carbon steel
TiAlN	PVD	800°C	Black-violet	High-speed machining, dry cutting, stainless, alloy steel
AlTiN	PVD	900°C	Black	Extreme heat, hardened steel, superalloys, dry machining
Al₂O₃	CVD	1200°C	Black/clear	High-speed steel finishing, excellent chemical resistance
CVD Diamond	CVD	700°C	Gray	Aluminum, graphite, composites, non-ferrous
CBN	Sintered	1000°C	Bronze/gold	Hardened steel >45 HRC, cast iron, powder metal
PCD	Sintered	700°C	Silver	Aluminum-silicon, composites, non-ferrous, graphite

CVD vs PVD Coatings

Property	CVD	PVD
Thickness	5-20 μm (thicker)	1-5 μm (thinner)
Process Temp	900-1100°C	200-500°C
Edge Sharpness	Slightly rounded	Sharp maintained
Adhesion	Excellent	Good
Best For	Heavy roughing, steel	Finishing, sticky materials
Edge Toughness	Good	Better

Material-Specific Recommendations

Material	ISO Grade	Recommended Coating	Speed Range	Notes
Low Carbon Steel (1018, 1020)	P15-P25	TiCN + Al₂O₃ (CVD)	150-300 m/min	Watch for built-up edge
Medium Carbon Steel (1045)	P15-P25	TiAlN or CVD multi-layer	120-250 m/min	Good machinability
Alloy Steel (4140, 4340)	P20-P35	TiAlN	100-200 m/min	Higher toughness needed
Stainless 304/316	M15-M25	TiAlN or AlTiN	100-180 m/min	Sharp edge, positive rake
Stainless 17-4 PH	M20-M30	AlTiN	80-150 m/min	Tougher grade, reduce speed
Gray Cast Iron	K10-K20	TiN + Al₂O₃	150-300 m/min	Abrasive, dry cutting OK
Ductile Cast Iron	K20-K30	TiCN + Al₂O₃	100-200 m/min	More abrasive than gray
Aluminum 6061	N10-N20	Uncoated or PCD	300-1000 m/min	Sharp edge, positive rake
Aluminum A356 (Cast)	N10-N20	CVD Diamond or PCD	200-600 m/min	Silicon is abrasive
Titanium Ti-6Al-4V	S15-S25	TiAlN or Uncoated	30-60 m/min	Low speed, high feed, coolant
Inconel 718	S20-S30	AlTiN or Ceramic	20-40 m/min	Very tough, work hardens
Hardened Steel 50 HRC	H10-H15	CBN	80-180 m/min	Rigid setup essential
Hardened Steel 60 HRC	H10	CBN (high content)	60-120 m/min	Light cuts only

Chipbreaker Selection

Chipbreakers control chip formation, breaking, and evacuation. Choose based on depth of cut and feed rate.

Chipbreaker	Type	DOC Range	Feed Range	Application
`-PF`	Light Finishing	0.3 - 1.5 mm	0.05 - 0.15 mm/rev	Fine finishing, tight tolerances, good surface
`-MF`	Medium Finishing	0.5 - 2.0 mm	0.10 - 0.25 mm/rev	General finishing, profiling
`-PM`	Medium	0.5 - 3.0 mm	0.15 - 0.35 mm/rev	General purpose, most common
`-MM`	Medium-Heavy	1.0 - 4.0 mm	0.20 - 0.40 mm/rev	Heavier roughing, good chip control
`-PR`	Heavy Roughing	1.0 - 6.0 mm	0.25 - 0.50 mm/rev	Maximum material removal
`-MR`	Roughing	2.0 - 8.0 mm	0.30 - 0.60 mm/rev	Heavy duty, interrupted cuts
`-GS`	Stainless	0.5 - 2.5 mm	0.10 - 0.30 mm/rev	Stainless steel specific
`-GM`	General	0.5 - 4.0 mm	0.15 - 0.40 mm/rev	Wide range, versatile
`-SM`	Superalloy	0.3 - 2.0 mm	0.08 - 0.20 mm/rev	Inconel, titanium, nickel alloys

Chip Control Tips:

If chips are too long: Increase feed or use a tighter chipbreaker
If chips are burning/blue: Increase coolant or reduce speed
If chips are nested: Wrong chipbreaker for the DOC/feed combination
If insert is chipping: Chipbreaker is too aggressive for the conditions

Quick Reference Charts

Insert Shape vs. Approach Angle Compatibility

Insert Shape	90°	75°	63°	45°	Best Use
`C` (80°)	Yes	Yes	Yes	No	Versatile, most common
`D` (55°)	Yes	Yes	Yes	Yes	Profiling, accessibility
`V` (35°)	Yes	Yes	Yes	Yes	Tight corners, weak
`T` (60°)	Yes	Yes	No	No	Economy, 3/6 edges
`S` (90°)	Yes	No	No	Yes	Heavy roughing
`W` (80°)	Yes	Yes	No	No	Heavy cuts, 6 edges
`R` (Round)	Yes	Yes	Yes	Yes	Strongest, any angle

Nose Radius Selection

Surface Finish Required	Feed Rate	Recommended Nose Radius
Ra 0.8 μm (Fine)	0.05-0.10 mm/rev	0.4-0.8 mm
Ra 1.6 μm (Good)	0.10-0.20 mm/rev	0.8-1.2 mm
Ra 3.2 μm (Medium)	0.20-0.35 mm/rev	0.8-1.6 mm
Ra 6.3 μm (Rough)	0.30-0.50 mm/rev	1.2-2.4 mm

Recommended Tool Holder Sizes

Shank Size (mm)	Insert IC	Max DOC	Machine Size
12×12	6-9 mm	2 mm	Small lathes
16×16	9-12 mm	3 mm	Light duty
20×20	12 mm	4 mm	Medium duty
25×25	12-16 mm	6 mm	General purpose
32×32	16-19 mm	8 mm	Heavy duty
40×40	19-25 mm	10+ mm	Large lathes

Threading Insert Selection

Thread Type	Profile Angle	Insert Code	Pitch Range
ISO Metric (M)	60°	16ER/IR AG60	0.5 - 6.0 mm
UN (UNC, UNF)	60°	16ER/IR UN60	4 - 28 TPI
Whitworth (BSW)	55°	16ER/IR W55	4 - 20 TPI
BSP/BSPP (G)	55°	16ER/IR W55	8 - 28 TPI
NPT/NPTF	60°	16ER/IR NPT	8 - 27 TPI
BSPT (R)	55°	16ER/IR BSPT	8 - 28 TPI
Acme	29°	16ER/IR ACME	2 - 16 TPI
Trapezoidal (Tr)	30°	16ER/IR TR30	1.5 - 12 mm

Thread Insert Sizing: The number before ER/IR indicates the insert size. 16ER = 16mm IC, 11ER = 11mm IC. Use full-profile inserts for best thread quality, or partial profile for multiple pitches.