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Metal drill bit fi 20,25 - NWKc HSS - Artykuły Techniczne
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  • Metal drill bit fi 20,25 - NWKc HSS - Artykuły Techniczne
  • Metal drill bit fi 20,25 - NWKc HSS - Artykuły Techniczne - nr. 1
Artykuły Techniczne

Metal drill bit 20.25 NWKc HSS DIN 345

€25.89 tax inc.

Net price: €21.05

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Description

DIAMETER Ø20.25 mm
MORSE TAPER MT2
OVERALL LENGTH 243 mm
FLUTE LENGTH 145 mm

Technical specifications of the Ø20.25 mm drill bit

Twist drill with Morse taper shank

TECHNICAL DATA
Diameter Ø20.25 NWKc HSS
Standard DIN 345
Drill type NWKc — twist drill with taper shank
Material HSS (high-speed steel)
Overall length l1 243 mm
Flute length l2 145 mm
Morse taper MT2
Point angle 118°
Diameter tolerance h8
Cutting direction Right-hand

Ø20.25 mm HSS metal drill bit – Morse taper MT2

Product description and key benefits

The Ø20.25 mm twist drill with an MT2 Morse taper is a standard tool for hole machining on stationary drilling machines. High-speed steel (HSS) provides cutting edge stability at speeds up to 25 m/min in structural steels. With a flute length of 145 mm, the Ø20.25 Morse taper drill allows through holes to be drilled in plates, flanges, and hollow sections.

Key benefits of the Ø20.25 mm metal drill bit

  • Direct mounting in an MT2 spindle — eliminates the drill chuck as a source of runout and slippage
  • Flute length 145 mm — drilling through holes in workpieces up to 130 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 Ø20.25 Morse taper drill is suitable for drilling holes in hollow sections, medium-thickness sheet metal, and components used in machinery repairs. H12 tolerance (Ø20.250–Ø20.460 mm) is sufficient for assembly holes; if H7 tolerance is required, additional reaming is necessary.

Morse tapers – dimensions to DIN 228

Dimension table for all Morse tapers MT0–MT6

TaperDiameter 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 Ø20.25 MM DRILL BIT:

✓ MT2 → MT3 — for a spindle with an MT3 socket
✓ MT2 → MT4 — for a spindle with an MT4 socket
✓ MT2 drill drift — for removing the drill bit from the spindle

Cutting data for the Ø20.25 mm drill bit according to ISO 513

Recommended machining conditions for a diameter of Ø20.25 mm

ISO symbolWorkpiece materialVc [m/min]f [mm/rev]n [rpm]Vf [mm/min]
P Steel Structural steel up to 900 N/mm² 11÷20 0.16 173÷314 28÷50
K Cast iron Gray cast iron GG20–GG30 13÷16 0.16 204÷252 33÷40
N Copper and Al alloys Cu, CuZn, Al, and alloys 25÷28 0.20÷0.25 393÷440 79÷110

Deep-hole drilling (over 3×D)

When drilling holes deeper than 60 mm (3ר20.25), periodically retract the drill every 1–1.5×D to remove chips. Use ample emulsion cooling (minimum concentration of 6–8%). Reduce the feed by 30–50% from nominal values.

Material compatibility of the Ø20.25 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 Ø20.25 mm drill bit

The HSS drill can be used for stainless steel with Vc reduced by 40% and ample cooling with a 8–10% emulsion. An HSSE (cobalt) drill of the same diameter is a more efficient option, retaining its hardness up to 650°C.

A pillar or box-column drilling machine with an MT2 spindle and a minimum power rating of 0.75–1.5 kW. Bench drilling machines with a drill chuck are not recommended — they cannot transmit the torque generated at a diameter of 20.25 mm.

It depends on the specific bolted joint. For metric coarse-thread bolts, the clearance hole diameter according to ISO 273 is 0.5–1 mm larger than the nominal thread diameter.

Product accessories

Morse drift MK1-2

Reference: 0000012383 In stock > 10 items

€3.95

€4.86 brutto

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Metal drill bit 20.25 NWKc HSS DIN 345

Metal drill bit 20.25 NWKc HSS DIN 345

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