1 Flute UP CUT Carbide End Mill (for Plastics)

A 1 flute up cut carbide end mill is purpose-built for cutting plastics cleanly and cool. It runs a single cutting edge with a large, open flute, and the up-cut spiral pulls chips up and out of the cut as it works. That aggressive chip evacuation is exactly what plastics need — it keeps the cutting zone clear, stops chips from being re-cut, and carries heat away before it can melt or re-weld the material. The result is a smooth, gummy-free finish in materials that would quickly melt or pack up behind a multi-flute bit.

The single flute is the key. With only one edge, each revolution takes a bigger, cleaner chip and leaves far more room to clear it — so the bit can run fast without generating the friction heat that melts acrylic and polycarbonate. Because the up-cut geometry lifts chips upward, it leaves the cleanest edge on the bottom face of the workpiece and clears deep slots without packing. The trade-off is the mirror image of a down-cut bit: chips exit on top, so it needs good hold-down and can leave a rougher top edge on thin or delicate stock.

Suitable for

• Acrylic (cast and extruded / PMMA) and polycarbonate (Lexan)
• ABS, HDPE, nylon, acetal (Delrin), PVC and most machinable plastics
• Foams, and soft timbers where fast chip clearance matters

Not ideal for

• Plys— the up-cut can fray or chip the top surface; use a down-cut bit instead
• Thin, unsupported sheet without solid hold-down — the upward pull can lift or chatter the material
• Hard metals and steel — this tool is optimised for plastics and soft materials, not ferrous cutting

Adam’s Tips

The most common problem cutting plastic is melting, and the fix is almost always counter-intuitive: if the edge is gummy or the chips are re-welding, increase your feed rate or drop your RPM. A single flute relies on a decent chip load — a bigger chip carries the heat out of the cut with it, while a slow feed just rubs and melts. Aim to keep the chips flowing and clearing, not powdering.

Because an up-cut bit pulls chips (and the material) upward, good work holding is essential — use a vacuum table, clamps, or tape-and-glue on thin sheet to stop it lifting.