Bits / Workshop reference
Downcut spiral bits
Protect the top face of a panel while making room for chips below the cut.
How it works
The flute geometry directs cutting action and chips toward the tip. This can reduce lifting of top-face fibers but can pack chips into a closed slot.
When to consider it
Consider downcut tooling for top-edge quality in an approved wood or sheet material when the cut has a workable chip-clearance strategy.
Where it does not apply
A clean top edge does not guarantee a clean bottom edge. Do not treat downward force as a substitute for clamps or vacuum hold-down.
Before the first cut
- Inspect the underside support and space for chip removal.
- Confirm the tool's permitted entry, depth and engagement with its manufacturer; do not assume it can drill a deep closed hole.
- Test the complete cut sequence on matching scrap, including the last pass and part retention.
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.
Burning in a slot
Stop; check packed chips, a dull edge and inappropriate engagement before changing feed or RPM.
Bottom-face breakout
Check support and compare a suitable compression tool where both faces matter.
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.
- Top/bottom face requirements
- Tool geometry and usable cutting length
- Extraction and underside support
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.