End mills overview and usage

[TODO: create overview of end mills in general, with specific recommendations for our spindle.]

Overview of end mill parameters

[TODO: figure out a way to organize this info in an easy-to-read way.]

• Flutes = 1, 2, 3 and more
• Flute type = straight, spiral and O
• Profile = flat, ball, bull, tapered, V
• Diameter = very small (PCB isolation/micromachining) to very large.
• Direction = up, down, and compression cut
• Composition = HSS, carbide, exotic coatings

Recommendations

For 2D routing

In general, stick with flat profile end mills in order to cut all the way through material with minimal spoilboard penetration.

• For cutting plywood = 1/2" or 1/4" flat nose, 2-flute (spiral), down cut (or compression cut). Might also be able to use conventional hand router bits, otherwise known as 1 or 2 flute (straight), flat nose.
  • Direction
    • Up cut can lift workpiece and/or cause ugly tearout on top surface.
    • Down cut won't lift workpiece, but can cause ugly tearout on bottom surface.
    • Compression cut is ideal, but more expensive.
  • Composition
    • Plywoods can be surprisingly tough on end mills due to resins
    • MDF in particular is very rough on end mills, as the fine dust can function as gritty abrasive.
• For cutting hardwoods
• For cutting plastics
  • [TODO: research O flutes]
• For cutting foams

For 3D milling

• Good to use multiple end mills per job for roughing, coarse detail, and finishing passes. Recommend same end mill used for 2D routing for roughing, followed by 1/8" ball nose for coarse detail, followed by 1/16-1/64" ball nose tapered for fine detail.
• Ball nose profile
• Small diameter means finer features
• Use tapered bits to bring down effective cutting diameter while maintaining strength, allowing for higher speeds.

For detailing and engraving

• V bits are popular for classical signage, but also impose a strict (though sometimes desirable) aesthetic.
• Small diameter means finer features.
• Look into PCB isolation / micromachining bits
• Flat nose probably preferable to ball nose.
• Flutes probably don't matter as much.

Where to buy

• McMaster
• ToolsToday
• Carbide3D
• Inventables