End Mills are used to create shapes and holes in a workpiece during milling, profiling, contouring, slotting, counterboring, drilling, and reaming applications. Featuring cutting edges on both the face and periphery, they can machine a wide range of materials in multiple directions. Explore the types of end mills, including carbide square end mills, available from MSC Industrial Supply and the applications they’re built for.
Your Guide to Perfect Milling
Understand end mill types, coatings, and tips to get the most from carbide square end mills and more.
Diagram of an End Mill
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Essential Summary
- For faster cuts and maximum rigidity, use shorter end mills with larger diameters.
- Variable helix end mills reduce chatter and vibration.
- Use cobalt, PM/Plus, or carbide for harder materials and high-production work.
- Apply coatings to increase feeds, speeds, and extend the tool life.
End Mill Types
Square End Mills
Square end mills are used for general milling applications including slotting, profiling and plunge cutting.
Keyway End Mills
Keyway end mills are made with undersized cutting diameters for a precise fit between the slot and woodruff key or keystock.
Ball End Mills
Ball end mills, also known as ball nose end mills, feature a rounded cutting edge for contouring, slotting, pocketing, and machining dies or molds.
Roughing End Mills
Roughing end mills, also known as hog mills, remove large amounts of material quickly during heavy cuts. Tooth design reduces vibration but leaves a rough finish.
Corner Radius End Mills
Corner radius end mills have a rounded cutting edge for applications requiring a specific radius. Corner chamfer end mills have an angled cutting edge and are used where a specific radius size is not required. Both types provide longer tool life than square end mills.
Roughing & Finishing End Mills
Roughing and finishing end mills perform heavy material removal and produce a smooth finish in a single pass.
Corner Rounding End Mills
Corner rounding end mills mill rounded edges with ground cutting tips that strengthen the tool and reduce chipping.
Drill Mills
Drill mills are multifunctional tools for spotting, drilling, countersinking, chamfering, and milling.
Tapered End Mills
Tapered end mills are cutting-edge tapers for use in die and mold applications.
Shank Styles:
Plain Shanks are used in conjunction with a collet-type holder.
Weldon Shanks feature one or two flats secured by set screws in the holder, preventing tool rotation during heavy cuts.
Flute Types
Flutes feature grooves or valleys cut into the tool body. More flutes create a stronger tool, produce a finer finish, and work best on harder materials, while fewer flutes provide more chip space, making them ideal for softer materials and aggressive cuts.
Single flute end mills are designed for high-speed machining and maximum material removal.
Two flute designs have the most amount of flute space. They offer the most chip clearance and are best for slotting and pocketing nonferrous materials.
Three flute designs have the same flute space as two flutes but also have a larger cross-section for greater strength. Ideal for pocketing and slotting ferrous and nonferrous materials.
Four/multiple flute end mills allow faster feed rates and product fine finishes, but due to the reduced flute space, chip removal may be a problem. Ideal for peripheral and finish milling.
End Cut Types:
Centercutting tools have one or more cutting edges at the tip and are used in a variety of applications including plunging, drilling or ramping.
Non-Centercutting applications have peripheral teeth allowing for the user to side (radial) cut or contour an exterior surface. Used in applications where plunge cutting is not necessary.
Cutting Tool Materials
High Speed Steel (HSS) provides good wear resistance and costs less than cobalt or carbide end mills. HSS is ideal for general-purpose milling of both ferrous and nonferrous materials.
Vanadium High Speed Steel (HSSE) combines HSS with carbon, vanadium carbide, and other alloys for greater wear resistance and toughness. Commonly used on stainless steels and high-silicon aluminums.
Cobalt (M-42: 8% Cobalt) offers higher wear resistance, hot hardness, and toughness than HSS. Resists chipping under severe cutting conditions, allowing the tool to run 10% faster than HSS, resulting in excellent metal removal rates and good finishes. It is a cost-effective material ideal for machining cast iron, steel, and titanium alloys.
Powdered Metal (PM) is more durable and cost-effective than solid carbide, with high resistance to breakage. Performs well in materials under 30 RC and in high-shock, high-stock applications such as roughing.
Solid Carbide offers superior rigidity and heat resistance compared to HSS, making carbide square end mills a top choice for precision slotting and profiling. Ideal for high-speed applications on cast iron, nonferrous metals, plastics, and other tough materials. Can run 2–3× faster than HSS, though heavy feed rates are better suited to HSS or cobalt tools.
Carbide-tipped features carbide brazed to steel tool bodies for faster cutting than HSS. Suitable for ferrous and nonferrous materials, including cast iron, steel, and steel alloys. A cost-effective choice for larger diameter tools.
Polycrystalline Diamond (PCD) is a shock- and wear-resistant synthetic diamond designed for extremely high-speed cutting of nonferrous materials, plastics, and extremely difficult-to-machine alloys.
Standard Coatings/Finishes
Titanium Nitride (TiN) is a general-purpose coating that provides high lubricity and increases chip flow in softer materials. The heat and hardness resistance allow the tool to run at higher speeds of 25% to 30% in machining speeds vs. uncoated tools.
Titanium Carbonitride (TiCN) is harder and more wear-resistant than Titanium Nitride (TiN). Ideal for stainless steel, cast iron, and aluminum alloys. TiCN can provide the ability to run applications at higher spindle speeds. Use caution on nonferrous materials due to galling risk. Requires an increase of 75-100% in machining speeds vs. uncoated tools.
Titanium Aluminum Nitride (TiAlN) has a higher hardness and oxidation resistance than TiN and TiCN. Performs well on stainless steel, high alloy carbon steels, nickelbased high-temperature alloys, and titanium alloys. Use caution in nonferrous material because of a tendency to gall. Requires an increase of 75% to 100% in machining speeds vs. uncoated tools.
Aluminum Titanium Nitride (AlTiN) is one of the most abrasive-resistant and hardest coatings for machining aircraft and aerospace materials, nickel alloy, stainless steel, titanium, cast iron, and carbon steel.
Zirconium Nitride (ZrN) is similar to TiN but has a higher oxidation temperature. Reduces sticking and edge build-up; ideal for aluminum, brass, copper, and titanium.
Uncoated tools do not feature supportive treatments on the cutting edge. They are used at reduced speeds for general applications on nonferrous metals.
Common Milling Problems & Solutions
Milling Formulas:
RPM = SFM x 3.82 ÷ Tool Diameter
IPM = RPM x # of Flutes x Chip Load
Chip Load = IPM ÷ RPM x Number of Flutes
SFM = .262 x Tool Diameter x RPM
Glossary:
Revolutions per Minute (RPM): Number of complete cutter rotations per minute.
Inches per Minute (IPM): Number of inches the cutter passes through the workpiece in one minute.
Chip Load: The amount that each flute cuts during a single revolution of a cutting tool.
Surface Feet per Minute (SFM): The cutting speed of the end mill in the United States. It is the number of feet per minute that a given point on the circumference of a cutter travels per minute.