End Mills
| ToolInfoBox End Mills | |
|---|---|
| |
| Synonyms: | DE: Schaftfräser |
| Type: | milling cutter |
| Material: | different |
| Used with: | CNC router, CNC mill |
| Location: | Wood Workshop |
| Access Requirements: | read this page; you may still need your own |
| Similar (More or Less): | router bits, drill bits |
End mills are used with our CNC router or CNC mill.
An end mill is a type of milling cutter, a cutting tool used in industrial milling applications. It is distinguished from the drill bit in its application, geometry, and manufacture. (Wikipedia) The most obious difference is that they don't cut by being inserted vertically into the workpiece but by being pushed laterally.
Characteristics
End mills come in different sizes and with different numbers of flutes (cutting edge and channel for chips). In addition, they can be made of different materials.
Some examples of variable parameters:
- shaft diameter: The part that the machine gabs on to so it has to match one of the available collets of the machine you'll use.
- cutting diameter: The diameter of the flutes/ cutting part. this determines the corner radius and the work time as thicker bits can tolerate more lead.
- tapering: Some bits are tapered to have a smaller tip with a stronger core.
- cut direction: determines surface finish and chip evacuation
- upcut: The chips are effectively transported out of the slot but especially wood or other material with grain has a worse tear out on the surface. Theses are the best choice for metals.
- downcut: The grain is pushed into the material so there is little to no tear out if you don't cut through, otherwise it's just on the other side. since chips are not really evacuated this shouldn't be used with metals as remaining chips are more troublesome here.
- compressing: This combines both of the previous versions as it has upcut on the bottom and downcut at the top. These kind of bits are only really useful when cutting material prone to tear out in one full depth cut (through all). Multiple passes would nullify the effect.
- number of flutes: Increasing the number of flutes trades chip clearance space for greater tool rigidity and smoother surface finishes, shifting the ideal application from soft, high-chip materials like aluminum and wood to harder metals like steel.
- material: This highly influences durability/lifespan and cost as certain coating are needed to effectively machine harder materials.
- ability to plunge (grundschneidend): can you "drill" straight into a workpiece or do you need to ramp down gradually?
The material you want to cut dictates the proper bit material and number of flutes. If you are unsure which end mill to use, please refer to our collection of milling experiences.
Types of Bits
| Type | Difference | Use Case |
|---|---|---|
| Flat (Square) End Mills | Flat cutting bottom with sharp 90° square corners. | General milling, plunge cutting, profiling, slotting, and creating clean, flat-bottomed pockets. |
| Ball Nose End Mills | Fully hemispherical, rounded tip. | 3D contouring, organic curves, mold making, and detailed relief carving; leaves smooth transitions between passes on curved surfaces. |
| Bull Nose (Corner Radius) End Mills | Flat bottom with slightly rounded corners. -> Mix between Flat and Ball Nose End Mills | Heavy roughing and high-feed milling. The rounded corners prevent chipping of the flute tips, dramatically increasing tool life compared to sharp square bits. Also where a round edge at the bottom of a pocket is needed. |
| Chamfer Mills | Angled tip (typically 45° or 60°). | Deburring sharp edges, creating chamfers, and cutting countersinks or bevels along part borders. |
| V-Bits / Engraving Bits | Sharp, pointed tip angled anywhere from 15° to 90°. | Precise V-carving, fine detail lettering, and PCB trace routing. |
Available at the Space
End mills are usually "bring your own" as there are way too many different types and quality levels out there and the risk of breaking them is quite high. However, for soft materials and at your own risk there is a simple set of cheap end mills available to share in the CNC area (if they haven't broken down yet).
Besides this selection, Lukas might let you borrow one of his end mills/router bits for a beer or so ;-)
And maybe some other members would share, too?
Further Reading
- Make: "The Skinny on End Mills"
- Kleine Fräserkunde (DE) - Zerspanungsbude forum post by "stefang", focused on metal milling but also good general information
- see also "longer" version (DE) - lacking some images from the forum post, though
