For most blind holes, choose a conventional right-hand spiral-flute tap to carry chips back toward the shank. For an open through hole, a spiral-point tap is usually the better choice because it pushes chips forward in the feed direction. The spiral flute vs spiral point tap decision also depends on chip clearance, material behavior and the tap manufacturer’s specifications.
Spiral Flute vs Spiral Point Tap: Key Differences
A conventional right-hand spiral-flute tap carries chips toward the shank, making it a common choice for blind holes. A typical spiral-point tap pushes chips ahead of the tool, making it well suited to open through holes. Flute hand and special tap designs can change those application rules.
| Consideration | Spiral-Flute Tap | Spiral-Point Tap |
|---|---|---|
| Typical chip flow | Toward the shank for a common right-hand design | Forward in the feed direction |
| Common application | Blind holes | Open through holes |
| Chip clearance | Chips must be able to leave toward the hole entrance | Chips need clearance ahead of the tap |
| Geometry selection | Flute hand and helix geometry affect chip flow | Point and chamfer design affect suitability |
Spiral-Flute Taps: Strengths and Uses
A spiral-flute tap has helical grooves along its body. In a common right-hand design, those grooves carry chips back toward the shank, which helps clear chips from a blind hole as the tap advances.
The drawback is that chip evacuation depends on the geometry and material. A spiral-flute tap can pack chips in a through hole when the material produces long, stringy chips. Flute hand matters too: some left-hand flute designs push chips forward. For a blind hole, check that the specified geometry suits the material, thread depth and available pre-hole depth.
Spiral-Point Taps: Strengths and Uses
A spiral-point tap directs chips ahead of the cutting tool. That makes it a practical choice for a through hole with an open exit and enough clearance in the feed direction. It can handle long, continuous chips in this application.
The drawback is that forward-moving chips need somewhere to go. A blind hole restricts that space, so a typical spiral-point tap isn’t the first choice. Some short-chamfer spiral-point designs can be used in blind holes when the tool manufacturer permits the application and adequate chip clearance is available.
Which Tap Should You Choose?
Choose a spiral-flute tap if:
- You’re threading a blind hole and need chips carried toward the entrance.
- The specified flute geometry suits your material and required thread depth.
- The tap manufacturer approves the available pre-hole depth and chamfer for the job.
Choose a spiral-point tap if:
- You’re threading a through hole with clearance for chips to exit ahead of the tap.
- The material produces long chips and the tap is specified for that material.
- The manufacturer permits the application if you’re considering a special design for a blind hole.
Before ordering, check the thread specification, required thread and pre-hole depths, chamfer and toolholder compatibility against the tap manufacturer’s instructions. You can also review our M6X1 TH2 SC HSS product page when comparing thread-tool options; confirm its specifications against your application before selecting it.
FAQ
Can a Spiral-Point Tap Thread Blind Holes?
Some short-chamfer designs can, if the manufacturer approves the application and there’s enough space for chips ahead of the tap. A conventional spiral-flute tap is the more common starting point for a blind hole.
Do All Spiral Flutes Pull Chips Back?
No. Common right-hand spiral-flute designs carry chips toward the shank, but some left-hand flute designs push chips forward. Check the specified flute geometry and thread hand.
Which Tap Handles Long Chips?
Both types can be suited to long-chipping material, depending on their geometry and application. For an open through hole, a spiral-point tap can push long chips out ahead of the tool; for a blind hole, choose a spiral-flute design specified for the material.