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Metal drill bit 28.25 NWKc HSS DIN 345 Zbrojovka
0394
Diameter (mm): 28,25301 sizes of this drill
33,13,23,33,43,53,63,73,83,944,14,24,34,44,54,64,74,84,955,15,25,35,45,55,65,75,85,966,16,26,36,46,56,66,76,86,977,17,157,27,257,37,47,57,67,77,757,87,988,18,28,258,38,48,58,68,78,88,999,19,29,259,39,49,59,69,79,759,89,91010,110,210,310,410,510,610,710,7510,810,91111,111,211,2511,311,411,511,611,711,811,91212,112,212,312,412,512,612,712,812,91313,113,213,2513,313,413,513,613,713,7513,813,91414,2514,414,514,751515,2515,515,751616,2516,516,751717,2517,517,751818,2518,518,751919,2519,519,752020,2520,520,752121,2521,521,752222,2522,522,752323,2523,523,752424,2524,524,752525,2525,525,752626,2526,526,752727,2527,527,752828,2528,528,752929,2529,529,753030,2530,530,753131,2531,531,753232,2532,532,753333,2533,533,753434,2534,534,753535,2535,535,753636,2536,536,753737,2537,537,7537,83838,538,753939,2539,539,754040,2540,54141,54242,54343,54444,54545,54646,546,75474848,54949,55050,55151,55252,553545556575858,55960616263646566676869707172737475767778798081828384858687888990919293949596979899100
€47.26 tax inc.
Net price: €38.42
Description
DIAMETER Ø28.25 mm
MORSE TAPER MT3
OVERALL LENGTH 296 mm
FLUTE LENGTH 175 mm
Technical specifications of the Ø28.25 mm drill bit
Twist drill with Morse taper shank
| TECHNICAL DATA | |
|---|---|
| Diameter | Ø28.25 NWKc HSS |
| Standard | DIN 345 |
| Drill type | NWKc — twist drill with taper shank |
| Material | HSS (high-speed steel) |
| Overall length l1 | 296 mm |
| Flute length l2 | 175 mm |
| Morse taper | MT3 |
| Point angle | 118° |
| Diameter tolerance | h8 |
| Cutting direction | Right-hand |
Ø28.25 mm HSS metal drill bit – Morse taper MT3
Product description and key benefits
The Ø28.25 mm metal drill bit with an MT3 Morse taper shank to DIN 345 belongs to the group of tools designed for machining medium- and large-diameter holes. At Ø28.25, type N flute geometry provides chip evacuation proportional to the volume of material being removed. The Ø28.25 Morse taper drill bit with a 118° point angle allows self-centering in steels with tensile strengths up to 900 N/mm² without spot drilling.
Key benefits of the Ø28.25 mm metal drill bit
- Direct mounting in an MT3 spindle — eliminates the drill chuck as a source of runout and slippage
- Flute length 175 mm — drilling through holes in workpieces up to 160 mm thick in a single pass
- DIN 345 — identical taper dimensions regardless of manufacturer — full interchangeability
- Type N right-hand helical flutes — a compromise between web rigidity and flute capacity
- h8 diameter fit — preliminary holes for reaming to H7 without additional boring
- Extended tool life with emulsion cooling — coolant increases cutting edge life by up to a factor of 2.5 compared with dry drilling
The Ø28.25 mm Morse taper drill bit is used to manufacture infrastructure components — columns, supports, brackets, and load-bearing frames. In steel construction, hole diameters of 23–31 mm correspond to M22–M30 bolts. An H12 tolerance of Ø28.250–Ø28.460 mm is sufficient for through holes.
Morse tapers – dimensions to DIN 228
Dimension table for all Morse tapers MT0–MT6
| Taper | Diameter D [mm] | Length [mm] |
|---|---|---|
| MT0 | 9.045 | 49.8 |
| MT1 | 12.065 | 53.5 |
| MT2 | 17.780 | 64.0 |
| MT3 | 23.825 | 80.5 |
| MT4 | 31.267 | 117.5 |
| MT5 | 44.399 | 149.5 |
| MT6 | 63.348 | 210.0 |
REDUCTION SLEEVES COMPATIBLE WITH THE Ø28.25 MM DRILL BIT:
| ✓ | MT3 → MT4 — for a spindle with an MT4 socket |
| ✓ | MT3 → MT5 — for a spindle with an MT5 socket |
| ✓ | MT3 drill drift — for removing the drill bit from the spindle |
Cutting data for the Ø28.25 mm drill bit according to ISO 513
Recommended machining conditions for a diameter of Ø28.25 mm
| ISO symbol | Workpiece material | Vc [m/min] | f [mm/rev] | n [rpm] | Vf [mm/min] |
|---|---|---|---|---|---|
| P Steel | Structural steel up to 900 N/mm² | 11÷20 | 0.20 | 124÷225 | 25÷45 |
| K Cast iron | Gray cast iron GG20–GG30 | 13÷16 | 0.20 | 146÷180 | 29÷36 |
| N Copper and Al alloys | Cu, CuZn, Al, and alloys | 25÷28 | 0.25÷0.32 | 282÷315 | 70÷101 |
Coolant selection for drilling diameters of 23–31 mm
At a diameter of 28.25 mm, the volume of chips removed is considerable — the helical flutes must evacuate a large amount of material. Use an emulsion at a concentration of 6–8% with a flow rate of at least 5 l/min. Without pressurized coolant, limit the depth of each pass to 56 mm.
Material compatibility of the Ø28.25 mm drill bit
Range of workpiece materials and application limitations
✓ Structural steel (S235, S355) up to 900 N/mm²
✓ Gray and ductile cast iron (GG20, GGG40)
✓ Low-carbon and medium-alloy steel
▲ Stainless steel (Vc reduced by 40%, ample coolant)
▲ Aluminum and Al alloys (emulsion coolant required)
✗ Hardened steels above 45 HRC
Frequently asked questions about the Ø28.25 mm drill bit
The HSS drill can handle stainless steel with Vc reduced by 40% and ample coolant. For regular INOX machining, an HSSE (cobalt) drill of the same diameter is recommended.
A pillar or box-column drill press with an MT3 spindle and a power rating of at least 1.5 kW. For diameters above 25 mm, power feed is recommended — manual feed will not provide uniform pressure.
An HSSE drill bit contains 5% cobalt, which increases heat resistance from 600°C to 650°C. The practical difference: HSSE performs much better in stainless and difficult-to-machine steels. When machining only carbon steels, the difference in tool life is minimal.
Product accessories
Reduction sleeve MK4 MK3 1751 PTPa DIN 228
Reference: 1180 In stock > 10 items
€18.42
€22.66 brutto
Reduction sleeve MK6 MK3 1751 PTPa DIN 228
Reference: 11965 In stock < 10 items
€36.84
€45.32 brutto
Reduction sleeve MK5 MK3 1751 PTPa DIN 228
Reference: 5702 In stock > 10 items
€26.32
€32.37 brutto
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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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