Spiral Point Tap Series: PO & SL Model Selection
The spiral-point tap range spans straight-flute (PO) and spiral-point (SL) models, including standard, stainless, high-carbon, hard-material, oil-hole and deep-hole designs. Models differ in material, cutting speed, evacuation and wear resistance, covering through-hole tapping from mild carbon steel to hard alloy steel. Correct selection lowers cutting torque, raises efficiency and extends tool life.
1. Range Overview
Spiral-point taps push chips forward, suit through holes and give low torque and high efficiency. The range splits into straight-flute (PO) and spiral-point (SL) families. Typical range is about M1.2–M48, with some models supporting UN and W imperial threads.
2. Straight-Flute (PO) Family (Manufacturer Example)
| Model | Use and material |
|---|---|
| IPO / PO / +PO | Standard; general carbon steel (e.g. SS400), about 5–15 m/min |
| PO OX / +PO OX | Oxide finish, better anti-adhesion and wear; oil-cutting |
| PO LH | Left-hand thread |
| PO V | Coated, good wear and anti-adhesion |
| LS-PO / LS-PO V | Long shank; deep or long holes |
| SU-PO | Stainless; sticky materials |
| HC-PO | High-carbon steel (e.g. S55C) |
| EH-PO | Hard material (about 25–35HRC) |
| PM-PO | Hard material (35–45HRC); mold and alloy steel |
| MC-PO | Internal coolant; better lubrication and evacuation |
| ZEN-P | Titanium alloy; high heat and wear resistance |
| S-PO | Deep holes; efficient coolant supply |
3. Spiral-Point (SL) Family (Manufacturer Example)
Spiral-point SL models combine forward evacuation with a spiral flute, keeping stable evacuation and low torque at high speed.
| Model | Material | Size range |
|---|---|---|
| AU+SL | High-performance through-hole; general steel to stainless | M3–M20 |
| SU+SL | Stainless and sticky (SUS304/303, aluminium, copper) | M3–M6 |
| ZET-P | Titanium alloy, high-strength lightweight | M3–M20 |
| F-SL | High speed (about 15–25 m/min); poor evacuation at low speed | M3–M12 |
| HDISL | Dry/MQL; carbon and alloy steel | M6–M20 |
| MHSL | Medium-hard (about 20–30HRC); S48C–S55C, quenched-tempered steel | M6–M16 |
※ The models, speeds and sizes are a manufacturer example; follow the tool maker's catalog for actual specs and conditions.
4. Selection Logic
| Basis | Suggested model direction (example) |
|---|---|
| Stainless | SU-PO / SU+SL |
| High-carbon steel | HC-PO / MHSL |
| Hard material | EH-PO / PM-PO |
| Titanium alloy | ZEN-P / ZET-P |
| Deep holes | S-PO / long-shank LS-PO |
| High-speed work | Standard/coated / F-SL |
For the concept see the Spiral-Point Tap Guide; for torque see the Torque Analysis; for the tool overview see the Thread Tool Chart; for pilot holes see the Metric Tap Drill Chart.
FAQ
Q: Straight-flute (PO) or spiral-point (SL)?
Both are spiral-point (forward evacuation) for through holes. PO is versatile with a full lineup; SL adds a spiral flute for more stable evacuation and lower torque at high speed, ideal for high-speed production and sticky materials. Choose by material and speed.
Q: Which model for stainless?
Stainless is sticky, so use a dedicated model (e.g. SU-PO or spiral SU+SL, manufacturer example) for better evacuation and anti-adhesion, with suitable cutting fluid and pilot hole to reduce galling and breakage.
Q: Can spiral-point taps do hard mold steel?
Use a hard-material model (e.g. EH-PO ~25–35HRC, PM-PO ~35–45HRC, manufacturer example). Standard spiral-points lack point strength and chip on hard material, so match model and coating to the hardness.
Q: What for deep through-hole tapping?
Use a long shank (LS-PO) or an internal-coolant/deep-hole model (e.g. S-PO, MC-PO, manufacturer example) so coolant reaches and chips clear, avoiding clogging deep in the hole.
For the full reading guides on this topic, see Thread Machining: A Complete Reading Guide and Chip Control: A Complete Reading Guide.
