Nitrided HSS Spiral Flute Taps – M2–M24 for Blind Holes
Nitrided HSS spiral flute machine taps for metric blind-hole threading from M2 to M24. The helical flute geometry carries chips back toward the shank for controlled evacuation from enclosed holes, while the nitrided surface provides increased surface hardness and wear resistance for repeated machine-tapping applications.
Product Specifications
10 Pieces per Size
1–3 Days for In-Stock Sizes
Dimensions / Thread Tolerance / Surface Treatment / OEM
Consistent Quality
Consistent geometry across repeat orders.
Flexible Orders
Small batches and mixed sizes available.
OEM Support
Custom marking, labels and packaging.
Standard & Custom
Standard sizes and custom configurations.
Nitrided HSS Spiral Flute Taps – M2–M24 for Blind Holes
Nitrided HSS spiral flute machine taps for metric blind-hole threading from M2 to M24. The helical flute geometry carries chips back toward the shank and out of enclosed holes, helping reduce chip accumulation around the cutting edges. A nitrided surface treatment increases surface hardness and wear resistance without changing the basic toughness of the HSS substrate. The listed range covers 14 metric coarse-thread sizes for CNC, tapping-center and general machine-tapping applications.
Key Configuration
Helical flutes guide chips back toward the shank, supporting reliable chip removal from blind holes where chips cannot exit through the bottom.
The nitrided finish increases surface hardness and wear resistance while retaining the toughness of the HSS tool substrate.
Fourteen listed metric coarse-thread sizes cover small precision threads through larger M24 machine-tapping requirements.
Key Product Advantages
Blind-Hole Geometry
Spiral flutes lift chips away from the cutting zone during blind-hole thread machining.
Hardened Surface Layer
Nitriding provides a hardened surface layer intended to improve wear resistance during repeated tapping.
Broad Metric Selection
Standard listed sizes extend from M2 × 0.4 to M24 × 3.0 for varied thread requirements.
Machine Tapping
Suitable for controlled CNC and machine tapping with correct alignment, synchronized feed and lubrication.
Tapping Applications
This series is primarily intended for metric blind-hole threading where chips need to be transported back through the flutes. Final suitability depends on the exact workpiece grade, hardness, hole depth, required thread tolerance and tapping conditions.
Application Note:
Blind-hole tapping requires sufficient clearance below the required full thread for the tap lead and evacuated chips. Confirm the hole depth, pilot-hole diameter and usable thread depth before production.
Workpiece & Application Selection
Related HSS Tap Series
Related HSS Tap SeriesFor other spiral flute, spiral point, straight flute and thread forming configurations, browse our HSS Tap Range.
M2–M24 Size Chart & Specifications
The listed series covers 14 metric coarse-thread specifications from M2 × 0.4 to M24 × 3.0. Major diameters range from 2 to 24 mm, listed tooth lengths from 11 to 37 mm, shank diameters from 2.9 to 18.9 mm and recommended drill-hole diameters from 1.6 to 21 mm. Use the complete thread size and pitch for selection, then confirm the required thread depth, holder compatibility and workpiece conditions.
Complete Size Range
| Size | Major Dia. (mm) | Pitch (mm) | Tooth Length (mm) | Shank Dia. (mm) | Drill Hole Dia. (mm) |
|---|---|---|---|---|---|
| M2 | 2 | 0.4 | 11 | 2.9 | 1.6 |
| M2.5 | 2.5 | 0.45 | 12 | 2.9 | 2.1 |
| M3 | 3 | 0.5 | 14 | 3.0 | 2.5 |
| M4 | 4 | 0.7 | 18 | 3.9 | 3.3 |
| M5 | 5 | 0.8 | 18 | 4.9 | 4.2 |
| M6 | 6 | 1.0 | 24 | 5.9 | 5.0 |
| M8 | 8 | 1.25 | 22 | 6.1 | 6.8 |
| M10 | 10 | 1.5 | 25 | 7.9 | 8.5 |
| M12 | 12 | 1.75 | 30 | 8.9 | 10.3 |
| M14 | 14 | 2.0 | 30 | 11.0 | 12.0 |
| M16 | 16 | 2.0 | 32 | 12.3 | 14.0 |
| M18 | 18 | 2.5 | — | 13.8 | 15.5 |
| M20 | 20 | 2.5 | 37 | 13.9 | 17.5 |
| M24 | 24 | 3.0 | — | 18.9 | 21.0 |
How to Select a Nitrided Spiral Flute Tap
Spiral Flute Tap Speed & Feed Setup
Starting speed depends on the workpiece grade and hardness, thread size, blind-hole depth, nitrided tool condition, lubrication and machine rigidity. Use application-specific cutting data whenever available rather than applying one cutting speed across the complete M2–M24 range.
Setting Feed
Feed per revolution: For single-start metric threads, synchronized feed per revolution must equal the thread pitch.
Feed calculation: Feed (mm/min) = spindle speed (RPM) × thread pitch (mm).
Example: For M6 × 1.0 at 300 RPM, synchronized feed is 300 mm/min. This illustrates feed calculation only and is not a material-specific cutting-speed recommendation.
For general reference, see our HSS Cutting Tools Speeds & Feeds Guide .
For other spiral flute, straight flute, spiral point and forming tap configurations, browse our HSS Tap Range .
For general HSS tool selection, see How to Choose HSS Cutting Tools .
View HY Taps Catalog — for additional tap sizes and threading configurations.
HSS Tap Customization
For requirements beyond the standard range, send your tap drawing or application details. Custom HSS cutting and forming taps can be reviewed for the following specifications.
| PARAMETER | CUSTOMIZATION OPTIONS |
|---|---|
| Thread Specification | Metric, UNC/UNF and pipe threads; special diameters, pitches and left-hand threads. |
| Thread Accuracy | Tap limits and oversize allowances to suit the required internal-thread tolerance and gauging requirements. |
| Tap Geometry | Straight flute, spiral flute, spiral point or forming design; chamfer and working geometry matched to the application. |
| Length & Reach | Overall length, threaded-section length and neck clearance to suit thread depth and component access. |
| Shank & Drive Square | Shank diameter, square dimensions and holding length to match the tapping holder. |
| Material & Surface Finish | HSS or cobalt HSS grades; uncoated, TiN or TiCN options, depending on the tap design and workpiece material. |
Options depend on tap type and size. Final specifications, minimum order quantity and lead time are confirmed with the quotation. Explore Custom Tooling Services
OEM & Private Label
Customer branding and packaging can be specified for distributor and tooling-brand orders.
Laser marking: Logo, thread size, product code and batch identification, subject to available shank space. Labels & packaging: Protective tubes, product labels and branded packaging to the approved artwork.
For a quotation: Send a drawing or thread specification, required tolerance, workpiece material and hardness, blind or through-hole details, thread depth and quantity. Include machine, holder and lubrication details for application-specific requests.
HSS Tap Quality & Inspection
HSS cutting and forming taps are checked against the confirmed product specification or approved drawing. Material verification, in-process dimensional checks and final inspection focus on thread accuracy, tool geometry and consistent identification before packing.
Key Inspection Points
Inspection items and acceptance criteria depend on the tap type, size and agreed requirements.
| INSPECTION ITEM | CHECK POINTS |
|---|---|
| Material & Hardness | HSS or cobalt HSS grade and material records; hardness requirements and verification agreed for the selected grade. |
| Thread Form & Accuracy | Thread size, pitch, profile and specified tap limits against the confirmed specification or drawing. |
| Working Geometry | Flutes, spiral point and cutting edges for cutting taps; forming lobes and lubrication grooves, where present, for forming taps. Chamfer geometry checked for each design. |
| Tool Dimensions | Threaded-section length, overall length, shank diameter and drive-square dimensions. |
| Runout & Surface Condition | Specified runout, burrs, chipped edges and visible defects on cutting or forming surfaces. |
| Coating & Identification | Specified surface finish or coating, visible condition, tool marking and label accuracy. |
Inspection documentation: Specify any required material records, dimensional reports or sample-thread validation before ordering. Availability and inspection scope are confirmed with the quotation.
Packaging & Batch Identification
Individual protective packaging helps prevent damage to tap threads and working surfaces. Labels identify the tool specification and order or batch reference. Models, quantities and packing details are checked before dispatch.
Export Packing & Delivery
Outer cartons, cushioning and export packing are selected for the order quantity and shipping method. Dispatch dates, freight and payment terms are confirmed with the order.
FAQ & Technical Support
Selection, blind-hole preparation, chip evacuation and ordering guidance for M2–M24 nitrided HSS spiral flute machine taps.
Product & Application FAQs
Which sizes are available in this series?
The supplied chart lists 14 metric coarse-thread sizes from M2 × 0.4 through M24 × 3.0, including M2, M2.5, M3, M4, M5, M6, M8, M10, M12, M14, M16, M18, M20 and M24.
What does the nitrided surface treatment do?
Nitriding hardens the surface layer of the HSS tap and is used to improve wear resistance while retaining the toughness of the underlying high-speed steel. Actual tool life still depends on workpiece material, tapping conditions, lubrication and hole preparation.
Why are spiral flute taps suitable for blind holes?
The helical flute geometry carries chips back toward the shank and out of the hole. This helps prevent chips from accumulating near the bottom of a blind hole, where they cannot exit through the opposite side of the workpiece.
How deep can these taps thread a blind hole?
Usable full-thread depth depends on the tap size, cutting lead, available tooth or flute length and bottom clearance. The listed tooth length should not automatically be treated as the maximum guaranteed full-thread depth. Provide additional hole depth for the tap lead and evacuated chips.
Which workpiece materials are suitable for this series?
Application suitability depends on the exact material grade, hardness and chip behavior. Provide the workpiece specification when selecting production cutting conditions, especially for stainless steel, alloy steel and other materials that generate high tapping torque or long chips.
How should I use the drill-hole sizes in the chart?
The listed drill-hole diameters are starting reference values for the corresponding metric thread sizes. Confirm the final pilot-hole diameter according to the workpiece material, required thread tolerance and gauging requirements before batch production.
Can these taps also be used for through holes?
This series is primarily configured for blind-hole tapping because the spiral flutes carry chips back toward the shank. For through holes where chips can be directed forward through the workpiece, a spiral point tap is generally a more application-specific choice.
What machine setup and tapping conditions are required?
Use accurate alignment, a compatible tapping holder, synchronized feed and suitable lubrication. Feed per revolution must match the metric thread pitch. Starting speed should be selected according to workpiece grade, hardness, tap size, blind-hole depth and machine rigidity.
Ordering & Customization FAQs
What information is needed for a quotation?
Provide the complete thread size and pitch, quantity per size, workpiece material and hardness, blind-hole depth, required full-thread depth and finished-thread tolerance. Include machine, holder, surface treatment, marking, packaging or dimensional requirements when applicable.
Can dimensions, thread tolerance or OEM branding be customized?
Custom dimensions, metric thread specifications, thread tolerance, surface treatment, laser marking and packaging can be reviewed according to the application and order quantity. Critical dimensions and inspection requirements should be confirmed before production.
Are sample orders and mixed M2–M24 sizes available?
Sample and mixed-size requests can be reviewed. MOQ, stock availability and dispatch timing depend on the selected sizes, quantities and customization. Send the required size-and-quantity list for confirmation.
Selection Guides
Use the HSS guide for general tool-material selection, compare tapping with thread milling where appropriate, and browse the HSS tap range for alternative blind-hole and through-hole tap geometries.
Catalog & Technical Downloads
HY Taps Catalog (PDF)General tap series reference. Use this product page’s Specifications & Sizes section for the current M2–M24 thread sizes and drill-hole reference values; specifications in other series may differ.
HSS Cutting Tools Speeds & Feeds Guide (PDF)General HSS tapping reference. Confirm starting conditions for the actual workpiece material, tap size and blind-hole depth. During synchronized tapping, feed per revolution must match the selected metric thread pitch.
Need Sizes, Pricing or Custom Options?
Send us the required tool type, sizes, quantities, workpiece material and any OEM or custom requirements. We will confirm suitable specifications, availability, lead time and quotation details.
Drawings, size lists and reference photos are welcome.
