End Mill Naming Convention
Learn how to read ONMY carbide end mill model numbers and understand processing type, cutter type, flute count, length structure, neck design and shank code before sending an RFQ.
This guide helps customers identify square end mills, ball nose end mills, corner radius end mills, long reach tools and custom carbide end mill requirements from catalogue model codes.
Try Model Number Decoder Send Model for ReviewExample Model Structure
Example: HMQ-4EL can be read as HMQ series + 4 flute + square type + long edge structure. Exact dimensions such as D, d, H and L should be confirmed from the size table or RFQ.
Why End Mill Model Numbers Matter
A carbide end mill model number usually contains information about the product family, application direction, cutter geometry, number of flutes, length structure and sometimes shank or neck design. Reading the model number helps avoid wrong tool selection and makes RFQ communication faster.
- Identify square, ball nose and corner radius tool types.
- Understand whether a tool is standard, long edge, long shank or extra-long structure.
- Connect catalogue models with workpiece material and machining applications.
- Send clearer model number, drawing, coating and dimension requirements for quotation.
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How to Read a Carbide End Mill Model Number
ONMY end mill model numbers can be read by separating the series, flute count, cutter type and length or structure codes.
| Model Part | Example | Meaning | How It Helps Selection |
|---|---|---|---|
| Series / Product Family | HMQ |
Economical carbide end mill family or catalogue product family. | Helps identify tool series and basic application direction. |
| Flute Count | 2, 3, 4 |
Number of cutting flutes. | Influences chip evacuation, rigidity, feed rate and surface finish. |
| Cutter Type | E, D, R, B, U |
Square, sharp corner, round corner, ball nose or U-groove direction. | Defines the machined feature and related product type. |
| Length Structure | L, X, H, G, M |
Long edge, extra-long edge, long shank, extra-long shank or short edge. | Helps choose tools for deeper cutting, extended reach or rigid machining. |
| Dimension Codes in Size Tables | D, d, H, L |
D = cutting diameter, d = shank diameter, H = flute length, L = overall length. | Used when confirming exact tool size and quotation details. |
Application and Material Direction Codes
Processing type codes help indicate the general machining direction, material group or product family.
| Code | Meaning | Typical Use | Related Resource |
|---|---|---|---|
Q |
Economical Type | Cost-effective general machining and standard milling applications. | Carbide End Mills |
P |
Universal Type | General-purpose carbide end mills for common materials. | Carbide End Mills |
M |
High Performance | Higher productivity applications and more demanding cutting conditions. | How to Choose End Mills |
V |
Stainless Steel | Stainless steel machining and heat-resistant cutting conditions. | End Mills for Stainless Steel |
H |
Hardened Steel | Hardened steel, mold steel and HRC material machining. | End Mills for Hardened Steel |
X |
High Hardness Steel | High-HRC materials and high hardness steel machining. | End Mills for High Hardness Steel |
S |
High Temperature Alloys / Titanium Alloys | Titanium, nickel alloys and difficult-to-machine heat-resistant alloys. | End Mills for Titanium Alloys |
AL |
Copper, Aluminum, Acrylic | Aluminum, copper, acrylic and non-ferrous material machining. | End Mills for Aluminum |
Tool Shape and Cutting End Codes
Cutter type codes describe the geometry of the cutting end and help identify the correct product page.
Square / Sharp Corner Protection
Used for square end mills and flat-bottom milling such as slotting, side milling and shoulder milling.
View Square End Mills →
Sharp Corner
Used when a sharper flat-end cutting corner is needed. Confirm edge design and material before quotation.
View Flat End Mills →
Round Corner / Corner Radius
Used for corner radius or bull nose end mills. This is not the same as a corner rounding cutter.
View Bull Nose End Mills →
Ball Nose
Used for ball nose end mills for 3D contouring, mold machining, curved surfaces and finishing.
View Ball Nose End Mills →
U-Groove
Used for special groove or profile tool requirements. Send drawing or sample for technical review.
View Special End Mills →
Non-Standard Cutter Geometry
If the code cannot fully describe your tool, ONMY can review drawings, samples or machining applications.
View Custom End Mills →
How Flute Count Affects End Mill Selection
Flute count affects chip evacuation, cutting rigidity, feed rate and surface finish.
| Code | Meaning | Typical Selection Direction | Related Page |
|---|---|---|---|
2 |
2 Flute | Good chip evacuation for aluminum, slotting, copper and non-ferrous materials. | 2 Flute End Mills |
3 |
3 Flute | Balanced chip evacuation, cutting stability and surface finish. | 3 Flute End Mills |
4 |
4 Flute | Better rigidity and finishing performance for steel, stainless steel and side milling. | 4 Flute End Mills |
5+ |
Multi-Flute | Used for finishing, hard materials or special productivity requirements after review. | Custom End Mills |
For a complete comparison, see End Mills by Flute Count.
Length Structure Codes vs Dimension Codes
ONMY model numbers may use length structure codes to describe long edge, long shank or extra-long designs. These codes are different from dimension marks in drawings.
| Code | Meaning in Model Number | When to Use | Related Resource |
|---|---|---|---|
blank |
Standard Length | General CNC milling where standard flute length and reach are enough. | End Mill Sizes |
L |
Long Edge | Deeper side milling or longer flute length requirements. | Long Reach End Mills |
X |
Extra Long Edge | Extra-long cutting edge length for deeper side wall machining. | Long Reach End Mills |
H |
Long Shank / Long Handle | Extended reach when the tool needs more access length. | Long Shank End Mills |
G |
Extra Long Shank / Extra Long Handle | Deep cavity or hard-to-reach areas with extra reach requirement. | Extra Long End Mills |
M |
Short Edge | Rigid machining, shallow cutting and reduced vibration applications. | End Mill Sizes |
P |
Reduced Neck / Reduced Diameter | Deep reach, clearance requirement and reduced neck custom tools. | Custom End Mills |
D |
No Reduced Neck / No Diameter Reduction | Standard structure where neck clearance is not required. | End Mill Sizes |
Example ONMY End Mill Model Breakdown
The examples below show how a model number can be understood before confirming exact dimensions.
| Model Example | Breakdown | Typical Meaning | Related Page |
|---|---|---|---|
HMQ-2E |
HMQ + 2 + E | 2 flute square end mill for general milling and slotting. | Square End Mills |
HMQ-4EL |
HMQ + 4 + E + L | 4 flute long edge square end mill for deeper side milling. | Square End Mills |
HMQ-2B |
HMQ + 2 + B | 2 flute ball nose end mill for contouring and profile milling. | Ball Nose End Mills |
HMQ-2BH |
HMQ + 2 + B + H | 2 flute long shank ball nose end mill for extended reach applications. | Ball Nose End Mills |
HMQ-4R |
HMQ + 4 + R | 4 flute corner radius / bull nose end mill for stronger edge milling. | Bull Nose End Mills |
HMQ-4RG |
HMQ + 4 + R + G | 4 flute extra-long shank corner radius end mill for deep reach applications. | Long Reach End Mills |
Try a Simple ONMY End Mill Model Decoder
Enter a basic ONMY-style model number such as HMQ-4EL, HMQ-2B or HMQ-4R. The decoder gives a quick reading of the series, flute count, cutter type and length structure.
This tool is for basic reference only. Please confirm exact D, d, H, L dimensions, coating, material and quantity with ONMY before ordering.
End Mill Model Decoder
Need Help Identifying an End Mill Model?
Send the model number, drawing, sample photo or machining application. ONMY can help check the tool type, dimensions, coating direction and suitable replacement or custom carbide end mill option.
Continue Reading Carbide End Mill Technical Guides
Use these related guides to confirm end mill dimensions, coatings, cutting parameters and tool selection.
End Mill Sizes
Check D, d, H and L dimension codes, metric sizes, inch sizes and custom size options.
View Size Guide →
End Mill Coatings
Compare AlTiN, TiAlN, AlCrN, DLC and diamond coating directions by material.
View Coating Guide →
Speeds and Feeds
Learn RPM, feed rate, chip load and basic starting parameter direction for carbide end mills.
View Speeds & Feeds →
How to Choose End Mills
Compare tool type, flute count, material, coating and machining application in one guide.
View Selection Guide →
Send Your End Mill Model Number or Drawing
If you already have an ONMY model number, please send it together with tool dimensions, workpiece material, coating requirement and quantity. If the model number is incomplete, a drawing or sample photo can help our team review the tool faster.
- Model number or old tool code
- Cutting diameter D, shank diameter d, flute length H and overall length L
- Workpiece material and hardness / HRC
- Coating requirement or current tool coating
- Quantity, drawing, sample photo or machining problem
Send Model for Review
End Mill Naming Convention FAQ
What is an end mill model number?
An end mill model number is a catalogue code used to identify the tool series, flute count, cutter geometry, length structure and sometimes other design features.
How do I read an ONMY end mill model number?
Separate the model into product family, flute count, cutter type and structure code. For example, HMQ-4EL can be read as HMQ series, 4 flute, square type and long edge structure.
What does R mean in an end mill model?
R usually means round corner or corner radius. It refers to a bull nose / corner radius end mill, not a corner rounding cutter.
What does B mean in an end mill model?
B usually means ball nose. Ball nose end mills are used for 3D contouring, curved surface machining, mold machining and profile finishing.
What is the difference between length code and dimension code?
Length codes such as L, H, G, X and M in model numbers describe length structure. Dimension codes in drawings are different: D means cutting diameter, d means shank diameter, H means flute length and L means overall length.
What information should I send for an end mill RFQ?
Please send the model number, cutting diameter D, shank diameter d, flute length H, overall length L, coating requirement, workpiece material, hardness, quantity and drawing if available.
Can ONMY help identify a tool from an old model number?
Yes. You can send the old model number, drawing, sample photo or machining application. ONMY can review the tool type and recommend a suitable catalogue or custom option.
Can ONMY make a custom end mill based on a model number or drawing?
Yes. ONMY supports custom carbide end mills according to drawing, sample or application requirements, including diameter, flute length, overall length, shank, coating, radius and flute count.
