WoodWorkCalc

Bits / Workshop reference

Upcut spiral bits

Clear chips upward from pockets and grooves while accounting for top-edge tear-out and lifting forces.

How it works

A helical edge shears along the wall and transports chips toward the shank. The axial cutting action can lift fibers at the top face.

When to consider it

Consider a manufacturer-rated upcut for pockets and slots where chip evacuation matters. Match the exact tool to solid wood, plywood or another approved material.

Where it does not apply

Do not rely on the bit to hold a thin workpiece down. A visible top veneer may need a different tool or finishing strategy.

ShankTip
Axial chip movement is toward the shank. Arrows do not indicate feed or spindle rotation. Concept diagram, not to scale; guards and fixtures are omitted.

Before the first cut

  1. Secure the stock against lifting and lateral movement; check the cutout remains held after separation.
  2. Use the documented flute count, cutting diameter and material-specific chip-load guidance in CAM.
  3. Check cutting length, holder clearance and permitted entry method; a spiral appearance alone does not establish plunge capability.

Review collet engagement & stickout · Review material setup & zero

If the result looks wrong

Stop the machine and make it safe to inspect before checking the tool or workpiece.

Fuzzy top edge

Check grain, sharpness, workholding and whether a downcut or suitable compression geometry better matches the face requirement.

Chips trapped in a pocket

Stop and inspect extraction and the toolpath. Do not reach into a moving machine.

Use the matching calculator

Calculator outputs describe geometry, time or cost—not permission to operate at those values.

Make the setup repeatable

In Machine & Bit Settings, keep these details in the standard fields, additional fields and setup notes. Record a test date only after testing that exact setup.

  • Tool part number and flute count
  • Material and measured thickness
  • Workholding and chip evacuation
  • Tested feed, RPM and depth

No cutting settings are automatically supplied or saved by this guide.

References & exact specifications

These public references explain the tool families or software features. Locate your exact part number and machine manual before setup; product families are not interchangeable.

Guidance reviewed September 2026. Diagrams are original simplified explanations, not manufacturer drawings.

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