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Metal drill bit 20.75 NWKc HSS DIN 345
059470
Diameter (mm): 20,75301 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
€15.86 tax inc.
Net price: €12.89
Description
DIAMETER Ø20.75 mm
MORSE TAPER MT2
OVERALL LENGTH 243 mm
FLUTE LENGTH 145 mm
Technical specifications of the Ø20.75 mm drill bit
Twist drill with Morse taper shank
| TECHNICAL DATA | |
|---|---|
| Diameter | Ø20.75 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 |
Ø20.75 mm HSS metal drill bit – Morse taper MT2
Product description and key benefits
The Ø20.75 mm NWKc twist drill with an MT2 taper falls within a diameter range where the torque generated during cutting exceeds the capacity of a typical drill chuck. DIN 345 specifies an MT2 taper with a diameter of 17.78 mm for these drill diameters — large enough to transmit the full load without slippage. With a flute length of 145 mm, the Ø20.75 Morse taper drill allows through drilling in standard steel sections.
Key benefits of the Ø20.75 mm metal drill bit
- Self-holding taper shank — MT2 transmits full torque to the cutting edges without intermediate components
- HSS with a hardness of 63–65 HRC — stable cutting of materials with tensile strengths up to 900 N/mm² without loss of sharpness
- Overall length of 243 mm — proportional to the drilling diameter — provides a balance between reach and rigidity
- General-purpose 118° geometry — suitable for most materials encountered in shop machining
- Sleeve compatibility — use on drilling machines with MT1 to MT3 spindles using reduction sleeves
- Repeated resharpening — HSS steel allows the cutting edge to be restored without loss of cutting properties
The Ø20.75 Morse taper drill is designed for drilling holes in steel components of various thicknesses — from thin sheet metal to thick-walled sections. The versatile diameter allows one tool to be used for multiple operations at a single workstation. H12 tolerance holes, Ø20.750–Ø20.960 mm; close fits require reaming.
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 Ø20.75 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 Ø20.75 mm drill bit according to ISO 513
Recommended machining conditions for a diameter of Ø20.75 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 | 169÷307 | 34÷61 |
| K Cast iron | Gray cast iron GG20–GG30 | 13÷16 | 0.20 | 199÷245 | 40÷49 |
| N Copper and Al alloys | Cu, CuZn, Al, and alloys | 25÷28 | 0.25÷0.32 | 384÷430 | 96÷138 |
Coolant selection when drilling diameters of 20.75
At a diameter of 20.75 mm, the volume of chips removed increases significantly — the helical flutes must evacuate more material per centimeter of depth. Use an emulsion with a concentration of 6–8% at a minimum delivery rate of 3 l/min. Without pressurized cooling, limit the depth of each pass to 62 mm.
Material compatibility of the Ø20.75 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 Ø20.75 mm drill bit
In S235/S355 structural steels, spot drilling is not necessary — the 118° angle provides self-centering. Spotting with a 90° NC spotting drill is recommended when drilling on uneven or inclined surfaces, where the drill may slip away from the marked point.
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 20.75 mm.
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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