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Machine tap M28x1 DIN 374/35 C HSSE Fra
0000007296
€71.21 tax inc.
Net price: €57.89
Description
Material HSSE
Thread size M28x1
ChamferC (2–3) threads
Standard DIN 374
Technical data for the M28x1 blind hole tap
| Technical Data | |
|---|---|
| Nominal Diameter d1 | M28x1 |
| Thread Pitch P | 1 mm |
| Helix Angle | 35° |
| Overall Length l1 | 140 mm |
| Flute Length l2 | 20 mm |
| Length l3 | 55 mm |
| Shank Diameter d2 | 20 mm |
| Square Drive Size a | 16 mm |
| Tap Drill Diameter | 27 mm |
| Chamfer | C (2÷3) P |
| Thread tolerance | 6H |
How a spiral flute tap evacuates chips from a blind hole
The 35° flute works like a screw conveyor
The flutes of this tap follow a right-hand helix at an angle of 35° to the axis. The tap rotates clockwise and advances into the hole. Chips cut by the chamfer enter the flute, and the helix carries them upward like the auger in a meat grinder. The bottom of the hole stays clear, and the cutting edges do not encounter packed chips. The M28x1 tap has a reduced shank to DIN 374: diameter 20 mm, square drive 16 mm.
1
The 35° spiral flute carries chips upward from the chamfer.
2
The stepped chip exits the hole and breaks into short pieces.
3
The tap rotates clockwise to cut a right-hand thread.
4
Chamfer C: 2–3 incomplete threads on the tapered lead.
5
Clearance below the tap tip – min. 2 thread pitches above the bottom.
6
Feed 1 mm/rev, equal to the pitch of the M28x1 thread.
M28x1 spiral flute machine tap – metric fine thread for industrial hydraulics
The M28x1 spiral flute machine tap is a professional tool from Fra for cutting metric fine threads in blind holes up to 2.5D deep. The 35° spiral flute design efficiently evacuates chips backward, eliminating the risk of jamming during blind-hole tapping. HSSE steel with 5% added cobalt guarantees a hardness of 65-67 HRC and thermal stability up to 650°C. Tolerance 6H in accordance with DIN 374 ensures the dimensional repeatability required in series production. The tool is designed for CNC operators, toolrooms, and maintenance departments.
Key benefits of the M28x1 spiral flute machine tap
- 35° spiral flute geometry directs chips backward during cutting, which is essential when tapping blind holes without the risk of damaging the hole bottom
- Durability enhanced by the addition of 5% cobalt allows operation at temperatures up to 650°C in the cutting zone without loss of the tool's mechanical properties
- Tolerance class 6H precision in accordance with DIN 374 guarantees full thread interchangeability and dimensional repeatability in series production
- Material versatility covering structural steels up to 900 MPa, austenitic stainless steels 304/316, aluminum, and copper and brass alloys
- Chamfer form C allows tapping close to the bottom of a blind hole with a minimal incomplete thread length of just 2-3 pitches
- Compatibility with ER40 holders and tapping chucks with axial compensation for CNC machining centers and automatic lathes
The M28x1 spiral flute tap is well suited to the production of valve blocks and industrial valves and fittings requiring leak-tight threaded connections. The fine pitch of 1 mm provides a larger contact area than the standard M28x3 thread. The tap drill diameter for the M28x1 thread is 27 mm according to metric fine thread tables.
Cutting data for the M28x1 blind hole machine tap
| Material | Cutting speed Vc [m/min] | Spindle speed n [rpm] | Feed f [mm/min] |
|---|---|---|---|
| PSteel | 5-20 | 57-227 | 57-227 |
| MStainless steel | 5-10 | 57-114 | 57-114 |
| KCast iron | 5-15 | 57-171 | 57-171 |
| NAluminum | 10-25 | 114-284 | 114-284 |
Thread preparation M28x1 in a blind hole
1 Spot drilling
NC spotting drill 90°
2 Drilling
Ø 27 mm
3 Tapping
M28x1
✓ Done!
Tolerance 6H
Standard: DIN 374 | Chamfer: C (spiral flute) | Application: blind holes
Tolerance 6H — metric thread tolerance classes
| Class | Accuracy | Application | Status |
|---|---|---|---|
| 4H / 4g | High | Precision connections, hydraulics | — |
| 6H / 6g | Standard | Machine building, general-purpose | SELECTED |
| 7H / 8g | Low | Large clearance, easy assembly | — |
6H = internal thread (nut, hole) | 6g = external thread (screw)
Frequently asked questions
The M28x1 HSSE machine tap for metric fine threads performs well in structural steels with a tensile strength up to 900 MPa, stainless steels, aluminum, and brass. The fine pitch of 1 mm ensures leak-tight connections in hydraulic applications up to 400 bar.
For the M28x1 metric fine thread in tolerance class 6H, the tap drill diameter should be 27 mm. The permissible hole tolerance range is 27.0-27.2 mm. A smaller hole increases cutting torque and the risk of tool breakage.
Yes, cooling with an oil emulsion at a minimum concentration of 8% or with tapping oil is recommended and extends tool life by a factor of 2-3. Intensive cooling is required when machining stainless steels, while aluminum can be tapped with minimal lubrication.
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Shipping
All orders are delivered by courier company GLS. For orders exceeding 369 PLN gross shipping is FREE
| Courier GLS | Przelew24 / Prepayment | 14,76 zł gross | Delivery time 1 working day |
| Courier GLS | Cash on delivery | 17,26 zł gross | Lead time 1 working day |
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