Solid Carbide End Mills · DIN 6527 Sizes

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Carbide End Mills & Solid Carbide End Milling Cutters

Solid carbide endmills for slotting, profiling, plunging and finishing in one setup — square, ball nose, corner radius, roughing and micro geometries in 2, 3, 4 and 5 flute configurations. Coatings run from TiAlN and AlTiN to TiCN, DLC and diamond, matched to steel, stainless steel, cast iron, hardened steel or aluminum. End mill diameters from 2 mm to 20 mm follow the DIN 6527 stepped-shank series, with inch and long-reach options. Send the material, operation and machine and we quote geometry, coating and starting cutting data.

Square, ball nose, corner radius, roughing, micro and long-reach endmills
2, 3, 4 and 5 flute geometries — 30°, 38° and 45° helix options
TiAlN, AlTiN, TiCN, DLC and diamond-coated carbide grades
Cutting diameters 2–20 mm to DIN 6527, metric and inch shanks
Unequal-index and variable-helix designs for chatter control

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Quotes within hours — email or WhatsAppWorldwide shipping from Guangzhou, China

End mill geometry: flute count, helix angle and coating explained

An end mill is a solid rotating cutter that removes material with its side edges and its end face at the same time. Unlike a drill, which only cuts at the tip in the direction of the hole, an end mill can plunge, ramp, slot, profile, cut a shoulder and face a surface — and it can do all of that in a single setup on a three-axis machine. The tool geometry is what makes that possible, and three design elements decide how it behaves: the number of flutes, the helix angle of those flutes, and the coating on the carbide substrate.

Flute count sets the balance between chip room and rigidity. Two flutes leave the largest gullet and clear soft, sticky chips at high feed; three flutes are the aluminum standard; four flutes reinforce the core for steel and stainless steel; five and six flute tools hold a finish at the feed rates high-speed toolpaths demand. Helix angle then decides where the cutting force goes — a low helix keeps edge strength for tough material, a high helix lifts chips out of the cut and reduces radial load. What is end milling, if not that combination? A cutting action that is defined entirely by the geometry you choose for the job.

Coating and grade place the tool on the hardness–toughness–heat triangle. Uncoated polished carbide slides through aluminum without adhesion; TiAlN and AlTiN keep their hardness at the temperatures steel and stainless steel generate; TiCN resists abrasive wear on cast iron; DLC and diamond coatings cut non-ferrous and composite work where chemical wear is the limit. Choose the geometry that fits the feature first, then the coating that survives the material, and tool life follows from those two decisions.

End Mill Types & Geometries

End mill sub-types — square, ball nose, corner radius, roughing and micro

Square

Flat 90° cutting corner

2, 3 or 4 flute

The general-purpose geometry, and the tool most shops reach for first: a flat end face that plunges and ramps, and a square corner that finishes a wall at 90°. Square end mills cover slotting, pocketing, facing and profiling on steel, stainless, aluminum and plastics alike.

Ball Nose

Full-radius cutting end

2 or 4 flute

Turns in every direction, so a raster toolpath leaves a smooth surface instead of steps. Ball nose end mills are the finishing geometry for contoured work — radius blending, curved surfaces, and any transition a square corner could only staircase.

Corner Radius

Square face with R0.2–R3.0 edge radius

4 flute (bull nose)

Bull nose geometry: the corner carries a defined edge radius while the wall shoulder stays square. The radius moves load away from the sharp corner, so the tool survives interrupted cuts and higher feed per tooth while still leaving a defined shoulder. Radius values run from R0.2 mm for fine work to R2–R3 mm for roughing.

2-Flute

Wide gullet, centre cutting

30° helix

The chip-evacuation geometry. With two flutes there is room for the long, soft chip aluminum and plastics produce, and the open gullet allows fast plunging. A 2 flute end mill is also the first choice for slotting, where the cutter is buried in the work over its full diameter.

4-Flute & 5-Flute

Reinforced core, unequal index

38° and 45° helix

More flutes mean more cutting edges in the work per revolution and a thicker core, which resists deflection and holds a finish. A 4 flute end mill is the steel and stainless workhorse; five and six flute versions finish hardened and heat-resistant material where feed per tooth drops at high spindle speed.

Micro

Small cutting head, reduced neck

2 or 3 flute

Below roughly 3 mm the limiting factor stops being the workpiece and becomes tool deflection — so micro end mills pair a reduced neck with a short flute length to keep the length-to-diameter ratio low. Used for fine features, engraving and small deep pockets.

Roughing

Chip-splitter profile

3 or 4 flute

A wave ground along the cutting edge breaks long chips into short, manageable pieces at aggressive depth of cut. Use it to clear bulk stock quickly, then follow with a square or corner radius tool for the finishing pass.

Long Reach & Lollipop

Reduced neck and ball head

2 or 4 flute

Long reach end mills keep the cutting diameter while necking the body down, so the tool reaches the floor of a deep pocket without rubbing the wall. The lollipop variant carries a ball on a narrow neck for undercut and radius work a standard cutter cannot enter.

Unequal index spacing and variable helix angles break up the harmonic that makes a long cutter sing, and both are quoted on request alongside the corner radius families used for high-feed roughing and heavy-duty machining — supplied together with the holder and collet that keep runout low.

Technical Specifications

End Mill Selection Guide — Flute Count, Helix Angle, Coating & Geometry

Steel & Alloy Steel (ISO P)

4 or 5 flute, TiAlN or AlCrN coated

A tough coated grade on a reinforced core for medium to high cutting speed, run dry or with coolant.

Stainless & Heat-Resistant (ISO M)

Unequal index, variable helix, AlTiN

Anti-vibration geometry and a hard coating limit work hardening and built-up edge on 304, 316 and duplex.

Cast Iron (ISO K)

4 flute, TiCN or uncoated

Wear-resistant grades with a strong edge for the scale and sand inclusions found in grey and ductile iron.

Aluminum & Non-Ferrous (ISO N)

2 or 3 flute, 45° helix, polished flutes

A large polished gullet and no adhesion-prone coating, run at high speed so soft chips never recut.

Superalloys & Titanium (ISO S)

5 flute, AlTiN, fine-grain substrate

A heat-resistant coating and a rigid core for low-speed passes that keep heat out of the cutting edge.

Hardened & Tool Steel (ISO H)

Hard-grade carbide above HRC 45

Stiffer geometry and a hard coating for light, fast finishing passes; CBN turning inserts take over where a cutter cannot reach.

Parameter	Technical Details / Standard Values
Flute count and helix angle selection	Two or three flute — aluminum, plastics and slotting, where chip room matters most. Four flute — the steel and stainless general-purpose choice, with the feed per tooth to match. Five or six flute — finishing steel, cast iron and superalloys at high spindle speed. Helix angle — 30° general purpose, around 38° for steel and stainless, 45° and above for aluminum and high-feed toolpaths.
Cutting diameter and shank diameter	DIN 6527 covers cutting diameters from 2 mm to 20 mm with a stepped parallel shank: below 6 mm the shank is 6 mm, from 6 mm upward the shank matches the cutting diameter. Intermediate diameters can be ordered with the shank and the lengths of the next larger cutting diameter.
Flute length and depth of cut	Short and long cutting-edge versions exist for the same diameter — a 6 mm end mill is offered with 10 mm or 13 mm of flute length — and overall length runs from about 54 mm to 104 mm across the series. Choose the shortest flute that reaches your depth of cut; anything longer than that is deflection.
Coatings and grades	TiAlN and AlTiN for steel, stainless and hardened work; TiCN where abrasive wear dominates on iron; DLC and diamond coatings for aluminum, graphite and composites; uncoated polished carbide where adhesion is the enemy. Send the material and we match substrate, coating and geometry together.
Geometry — square, corner radius and ball nose	Square for 90° shoulders and flat floors; corner radius from R0.2 mm to R3.0 mm to strengthen the corner on feed-heavy roughing; ball nose for contoured surfaces and radius blending. On a corner radius tool, step down into a deep feature instead of plunging straight in.
Unequal index and variable helix	Evenly spaced flutes hit the same frequency every revolution and set up chatter. Unequal spacing and a variable helix break that pattern, widen the stable speed window and improve wall finish — which is why they are standard on stainless and long-reach tools.
Long reach and reduced neck	Deep pockets and narrow walls need reach without rubbing the wall above the cut. Necked and long-reach end mills trade a little rigidity for that clearance, so keep the projection as short as the part allows and reduce radial engagement rather than feed rate.
Dry cutting and coolant strategy	Coated carbide tolerates dry cutting and minimum-quantity lubrication on steel; aluminum usually wants flood coolant or a strong air blast so chips never weld to the edge; deep pockets and heat-resistant alloys gain most from through-tool coolant.
Regrinding and tool life judgement	A worn margin, a rising spindle load or a bright polished wear land on the flank all mean the edge has gone. Carbide end mills in the 3 mm to 20 mm range can be reground to the same geometry, though a coated tool loses its coating surface and should be recoated for stainless and hardened work.

Need a cutting diameter, corner radius, neck length, flute count or coating outside the standard series? Send the drawing or 3D model and we will source the end mill and the matching holder — trial quantities and mixed items welcome.

Applications

Which end mill for which material

Aluminum & Non-Ferrous

Two and three flutes with a 45° helix and polished margins clear soft chips at high speed, and an uncoated edge keeps aluminum from welding to the cutting surface.

See Application

Steel & Alloy

Four and five flute square end mills in TiAlN or AlCrN coated carbide hold a finish at the feed rates modern toolpaths allow, from plain carbon steel to alloy grades above 300 HB.

See Application

Stainless & Heat-Resistant

Unequal-index, variable-helix geometry with an AlTiN coating limits work hardening and chatter on 304, 316 and duplex material, where a plain four flute tool starts to sing.

See Application

Hardened Steel above HRC 45

Hard-grade carbide in five and six flute geometries takes light, fast finishing passes on hardened tool steel; where the feature suits a single-point cut, CBN turning inserts replace the cutter.

See Application

Tell us the workpiece material, hardness and machine — we reply with a recommended end mill, coating and starting cutting data instead of a catalogue page.

End Mill Sizes & Standards

End mill sizes, shank diameters and overall lengths to DIN 6527

End mill family	Geometry & flute count	Cutting dia. (d1)	Shank dia. (d2)	Flute length (l2)	Overall length (l1)	Typical application
Square end mills	Flat 90° corner, 2 to 4 flute	2–5 mm on a 6 mm shank; 6–20 mm 1:1	6–20 mm stepped shank	K 5–26 / L 8–38 mm	K 50–92 / L 57–104 mm	Slotting, pockets, shoulders and ramping
Ball nose end mills	Full radius, 2 to 4 flute	2–5 mm on a 6 mm shank; 6–12 mm 1:1	6–12 mm stepped shank	K 5–26 / L 8–35 mm	K 50–73 / L 57–83 mm	Contoured surfaces and radius blending
Corner radius (bull nose)	Square face, R0.2–R3.0, 4 flute	As square end mills	6–20 mm stepped shank	K 5–26 / L 8–38 mm	K 50–92 / L 57–104 mm	High-feed roughing and stronger shoulders
2-flute end mills	Wide gullet, centre cutting, 30° helix	2–5 mm on a 6 mm shank; 6–12 mm 1:1	6–12 mm stepped shank	K 5–26 / L 8–35 mm	K 50–73 / L 57–83 mm	Aluminum slotting and plunge work
4-flute and 5-flute	Reinforced core, 38–45° helix	6–16 mm 1:1 shank	6–16 mm stepped shank	K 10–22 / L 13–32 mm	K 54–82 / L 57–92 mm	Steel and stainless finishing cuts
Micro end mills	Reduced neck, 2 to 3 flute	0.5–3 mm nominal	3–6 mm shank, short flute	K 3–15 mm typical	K 38–50 mm typical	Fine features and small part profiling
Roughing end mills	Chip-splitter profile, 3 to 4 flute	6–20 mm 1:1 shank	6–20 mm stepped shank	K 10–26 / L 13–38 mm	K 54–92 / L 57–104 mm	Heavy stock removal ahead of the finishing pass
Long reach and lollipop	Reduced neck, ball head option	3–12 mm cutting dia.	Reduced neck below shank dia.	Extended neck, to drawing	L 57–83 mm typical	Deep pockets and undercut profiles

K = short cutting-edge version, L = long cutting-edge version per DIN 6527; micro and long-reach rows are typical ranges — exact sizes to drawing on request.

DIN 6527 standardises solid carbide end mills with a stepped parallel shank in cutting diameters from 2 mm to 20 mm: the cutting diameter is held to h10 and the shank to h6, short (K) and long (L) cutting-edge versions exist for the same diameter, and intermediate diameters can be ordered using the shank and lengths of the next larger size. That is why an end mill sizes list never looks quite regular — a 5 mm cutter carries the same 6 mm shank as a 2 mm or 3 mm one, while a 6 mm cutter switches to a shank that matches its own diameter. Working in inch, standard end mill sizes are quoted in fractions from 1/8 in to 3/4 in on the same geometries. Send the diameter, flute count and reach and we will confirm the end mill dimensions against the tool you are replacing.

Machining reference tools

Why Buyers Work With InsertCore

Sourcing, verification and support around your end mill programme

Geometry consistency & batch traceability

Every batch arrives with the diameter, flute count, helix and coating that were quoted. Dimensional reports and material certificates are available on request for incoming inspection.

Custom & non-standard tooling

Non-standard cutting diameters, neck lengths, corner radii, flute counts and coating combinations are quoted to your drawing or 3D model — including small trial quantities before a production order.

Sourced and QC-verified supply, one contact

We are a trading operation, not a production plant: end mills are sourced from vetted tooling partners and checked before dispatch, and the same contact stays with your programme from quote to delivery.

Quote turnaround

Within hours

Channels

Email + WhatsApp

Shipping

Worldwide, tracked

Quantities

Trial to bulk

Questions Buyers Ask

End mill selection and coating questions, answered

Should I use a 2 flute or a 4 flute end mill?

Two flutes leave a large gullet, so they clear the long soft chips aluminum and plastics produce and allow fast plunging and slotting — three flutes have become the aluminum standard for the same reason. Four flutes put more edges into the work per revolution and strengthen the core, which is what steel, stainless steel and cast iron need. The rule of thumb is that soft and sticky material goes to fewer flutes and hard material to more. Cutting a slot as deep as the cutter is wide in aluminum, stay with two or three flutes.

Ball nose, square or corner radius — how do I choose the geometry?

Square gives a flat floor and a 90° shoulder, and it is the right answer for pockets, slots and square edges. Ball nose cuts in every direction and blends one surface into the next, so it finishes contoured work that a square corner would leave stepped. Corner radius sits between the two: a square end with a defined radius that keeps the shoulder but moves cutting load away from the sharp corner. Rough with the strongest geometry that fits the feature, then finish with the one that produces the surface you need.

Which coating should I choose — TiAlN, AlTiN, DLC or diamond?

Match the coating to the failure you are trying to avoid. TiAlN is the general-purpose choice for steel and runs dry or wet. AlTiN holds its hardness at higher temperature, which is why it is used on stainless steel, titanium and hardened material. TiCN resists abrasive wear on cast iron. DLC and diamond coatings cut aluminum, graphite and composites without the chemical adhesion that destroys a plain carbide edge. Uncoated polished carbide is still the best answer for aluminum when you want the sharpest possible edge.

What end mill should I use for aluminum?

Two or three flutes, a 45° or higher helix, polished flutes and no coating — or a DLC coating if you are running production. The large gullet clears soft chips, the high helix lifts them out of the cut instead of recutting them, and the polished surface stops aluminum welding to the edge. Run at high spindle speed with flood coolant or a strong air blast, and keep the axial depth of cut moderate until the setup has proved itself rigid.

End mill or drill bit — which one do I need?

A drill bit cuts in one direction, at its tip, and produces a round hole on the axis of the tool. An end mill cuts with its sides and its end, so it can ramp, slot, profile and face as well as plunge: face milling and end milling are both side-and-end cutting operations, while drilling only removes material ahead of the point. If the feature is a hole on centre, drill it. If it is a slot, a shoulder, a pocket or a profile, use an end mill.

What end mill do I need for hardened steel above HRC 45?

A hard-grade carbide tool in a five or six flute geometry, run light and fast with a small radial engagement and as short a projection as the part allows. Above HRC 45 the edge carries very high local load, so chip thinning and a stable toolpath matter more than raw feed rate. Where the feature allows a single-point cut instead, CBN turning inserts or ceramic inserts remove hardened steel more economically than a small cutter.

How do you control end mill quality?

End mills are sourced from vetted tooling partners and inspected before dispatch. Cutting diameter, flute count, helix angle and coating are confirmed against the quotation, dimensional reports and material certificates are supplied on request, and each shipment is packed for transit. If a batch does not perform as confirmed, send the batch reference and your measurements and we will put it right.

What information should I send for an accurate end mill quote?

The workpiece material and hardness, the operation (slotting, profiling, facing, roughing or finishing), the machine and holder interface, the cutting diameter and flute count you need — or a drawing or 3D model if it is a special — and the quantity. With those five points we can quote a matched geometry and coating instead of a catalogue item.

How fast can I get pricing, and how are orders shipped?

Quotations are normally issued within hours during business hours — email and WhatsApp reach us directly. Orders ship worldwide from Guangzhou, China with tracking, and payment terms are stated on the quotation. Trial quantities and mixed-item orders are both welcome.

Get your end mill quote within hours

Send the cutting diameter, flute count, coating, workpiece material and quantity — you get pricing, availability and starting cutting data, not a catalogue.

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