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Metal drill bit 7.7 NWKc HSS DIN 345
Net price: €3.68
Description
Technical specifications of the Ø7.7 mm drill bit
Twist drill with Morse taper shank
| TECHNICAL DATA | |
|---|---|
| Diameter | Ø7.7 NWKc HSS |
| Standard | DIN 345 |
| Drill type | NWKc — twist drill with taper shank |
| Material | HSS (high-speed steel) |
| Overall length l1 | 156 mm |
| Flute length l2 | 75 mm |
| Morse taper | MT1 |
| Point angle | 118° |
| Diameter tolerance | h8 |
| Cutting direction | Right-hand |
Ø7.7 mm HSS metal drill bit – Morse taper MT1
Product description and key benefits
The Ø7.7 mm NWKc twist drill is distinguished by its mounting method — the MT1 Morse taper eliminates the intermediate component between the tool and the spindle. This results in lower radial runout and improved repeatability of hole dimensions. The Ø7.7 Morse taper drill with a high-speed steel (HSS) cutting edge retains its working hardness up to 600°C, allowing drilling without the risk of tempering the cutting edge.
Key benefits of the Ø7.7 mm metal drill bit
- Eliminates the drill chuck — the MT1 taper seated directly in the spindle shortens the torque transmission path and reduces radial tool runout
- Heat resistance up to 600°C — the high-speed steel cutting edge retains its working hardness even at higher cutting speeds in soft and medium-hard steels
- Interchangeability to DIN 345 — identical taper dimensions across manufacturers allow drill replacement without calibrating the spindle axis
- Short design (l1 = 156 mm) — reduced tool overhang provides greater rigidity and a better hole surface finish than extended-length drills
- Holes for locating pins and bushings — the h8 tolerance grade provides a repeatable preliminary size before finish reaming to an H7 fit
- Low operating cost — can be resharpened repeatedly on a tool grinder without losing cutting geometry while maintaining the 118° angle
The Ø7.7 mm Morse taper drill is selected for repair and assembly work on pillar drilling machines. The tool allows fast drilling of through and blind holes in steels with tensile strengths up to 900 N/mm². H12 tolerance at Ø7.700–Ø7.850 mm provides dimensional accuracy sufficient for most bolted connections.
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 Ø7.7 MM DRILL BIT:
| ✓ | MT1 → MT2 — for a spindle with an MT2 socket |
| ✓ | MT1 → MT3 — for a spindle with an MT3 socket |
| ✓ | MT1 drill drift — for removing the drill bit from the spindle |
Cutting data for the Ø7.7 mm drill bit according to ISO 513
Recommended machining conditions for a diameter of Ø7.7 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 | 0.08 | 455÷827 | 36÷66 |
| K Cast iron | Gray cast iron GG20–GG30 | 13÷16 | 0.08 | 537÷661 | 43÷53 |
| N Copper and Al alloys | Cu, CuZn, Al, and alloys | 25÷28 | 0.10÷0.12 | 1033÷1157 | 103÷139 |
Drill sharpening
Sharpen the Ø7.7 mm drill bit on a tool grinder, maintaining the 118° point angle and cutting edge symmetry. Asymmetric sharpening enlarges the hole diameter and loads the spindle unevenly. Each sharpening reduces the flute length by approximately 1–2 mm.
Material compatibility of the Ø7.7 mm drill bit
Range of workpiece materials and application limitations
Frequently asked questions about the Ø7.7 mm drill bit
The maximum drilling depth is the flute length l2 = 75 mm minus the drill point length (approximately 2 mm). The effective usable depth is therefore approximately 73 mm.
In S235/S355 structural steels, spot drilling is not necessary — the 118° angle provides self-centering. Spot drilling with an NC 90° drill is recommended when drilling on milled surfaces, castings with machining allowance, or difficult-to-machine materials.
A cooling and lubricating emulsion at a concentration of 5–8% is recommended. For stainless steels, increase the concentration to 8–10%. Cast iron can be drilled dry with compressed air to remove chips.
Product accessories
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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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