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Description
DIAMETER Ø20.5 mm
MORSE TAPER MT2
OVERALL LENGTH 243 mm
FLUTE LENGTH 145 mm
Technical specifications of the Ø20.5 mm drill bit
Twist drill with Morse taper shank
| TECHNICAL DATA | |
|---|---|
| Diameter | Ø20.5 NWKc HSSE |
| Standard | DIN 345 |
| Drill type | NWKc — twist drill with taper shank |
| Material | HSSE (cobalt 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 |
Ø20.5 mm HSSE twist drill – MT2 Morse taper
Product description and key benefits
The Ø20.5 mm twist drill with an MT2 shank offers a significant advantage over straight-shank drills: mounting stability increases with load. The self-holding Morse taper seats deeper in the spindle in proportion to the cutting torque. At a diameter of 20.5 mm, the Ø20.5 Morse taper drill provides vibration-free operation and uniform cutting edge wear even during intensive use.
Key benefits of the Ø20.5 mm metal drill bit
- Cobalt 5% — hardness up to 67 HRC — greater hardness than standard HSS (63–65 HRC) translates into longer service life between sharpenings
- MT2 Morse taper to DIN 345 — secure, self-holding mounting regardless of load level
- Cutting-edge stability in INOX steels — HSSE does not require as drastic a reduction in Vc as HSS when drilling acid-resistant steels
- Flute length 145 mm — allows drilling through standard structural component thicknesses
- Versatility — drilling structural steels, stainless steels, cast iron, and aluminum with one tool
- 118° angle — self-centering in most materials without spot drilling
The Ø20.5 Morse taper drill is used in structural steel fabrication plants, toolrooms, and machinery service shops. Typical applications include mounting holes for bolts, pins, and bushings in steel flanges, plates, and sections. Hole tolerance class H12 (Ø20.500–Ø20.710 mm); H7 fits require reaming with a finishing reamer.
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 Ø20.5 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 Ø20.5 mm drill bit according to ISO 513
Recommended machining conditions for a diameter of Ø20.5 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 | 0.16 | 171÷311 | 27÷50 |
| K Cast iron | Gray cast iron GG20–GG30 | 13÷16 | 0.16 | 202÷248 | 32÷40 |
| N Copper and Al alloys | Cu, CuZn, Al, and alloys | 25÷28 | 0.20÷0.25 | 388÷435 | 78÷109 |
Deep-hole drilling (over 3×D)
When drilling holes deeper than 61 mm (3×Ø20.5), 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 Ø20.5 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 30%, ample coolant)
▲ Aluminum and Al alloys (emulsion coolant required)
✗ Hardened steels above 45 HRC
Frequently asked questions about the Ø20.5 mm drill bit
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 20.5 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.
Use cooling with a 5–8% emulsion, do not exceed the recommended cutting parameters, and resharpen the tool before it becomes completely dull. Clean taper and spindle socket surfaces reduce runout — the main cause of accelerated wear.
Product accessories
Long reduction sleeve MK1-2 PTPb 1762
Reference: 0000006908 In stock > 10 items
€15.79
€19.42 brutto
Reduction sleeve MK4 MK2 1751 PTPa DIN 228
Reference: 1181 In stock > 10 items
€15.79
€19.42 brutto
Reduction sleeve MK5 MK2 1751 PTPa DIN 228
Reference: 4910 In stock > 10 items
€22.37
€27.51 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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