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Metal drill bit 31.75 NWKc HSS DIN 345 Baildon
0406
Diameter (mm): 31,75301 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
€50.17 tax inc.
Net price: €40.79
Description
DIAMETER Ø31.75 mm
MORSE TAPER MT4
OVERALL LENGTH 334 mm
FLUTE LENGTH 185 mm
Technical specifications of the Ø31.75 mm drill bit
Twist drill with Morse taper shank
| TECHNICAL DATA | |
|---|---|
| Diameter | Ø31.75 NWKc HSS |
| Standard | DIN 345 |
| Drill type | NWKc — twist drill with taper shank |
| Material | HSS (high-speed steel) |
| Overall length l1 | 334 mm |
| Flute length l2 | 185 mm |
| Morse taper | MT4 |
| Point angle | 118° |
| Diameter tolerance | h8 |
| Cutting direction | Right-hand |
Ø31.75 mm HSS metal drill bit – Morse taper MT4
Product description and key benefits
The Ø31.75 mm twist drill with an MT4 taper shank conforming to DIN 345 is designed for drilling mounting holes in foundation plates, flanges, and machine housings. At a diameter of 31.75 mm, the axial force and torque require a stable machine platform — a pillar or box-column drilling machine with power spindle feed. The Ø31.75 Morse taper drill with a flute length of 185 mm enables drilling through holes in components with thicknesses commonly encountered in machine building.
Key benefits of the Ø31.75 mm metal drill bit
- Self-holding taper shank — MT4 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 334 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 MT3 to MT5 spindles using reduction sleeves
- Repeated resharpening — HSS steel allows the cutting edge to be restored without loss of cutting properties
The Ø31.75 Morse taper drill is chosen for heavy-duty hole machining in machine building, ship repair yards, and valve and fitting factories. Typical applications: holes in end plates, bearing end shields, and drive components. Hole tolerance class H12 (Ø31.750–Ø32.000 mm); tighter fits are achieved by boring.
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 Ø31.75 MM DRILL BIT:
| ✓ | MT4 → MT5 — for a spindle with an MT5 socket |
| ✓ | MT4 → MT3 — for a spindle with an MT3 socket |
| ✓ | MT4 drill drift — for removing the drill bit from the spindle |
Cutting data for the Ø31.75 mm drill bit according to ISO 513
Recommended machining conditions for a diameter of Ø31.75 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 | 110÷201 | 22÷40 |
| K Cast iron | Gray cast iron GG20–GG30 | 13÷16 | 0.20 | 130÷160 | 26÷32 |
| N Copper and Al alloys | Cu, CuZn, Al, and alloys | 25÷28 | 0.25÷0.32 | 251÷281 | 63÷90 |
Deep-hole drilling (over 3×D)
When drilling holes deeper than 95 mm (3×Ø31.75), 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 Ø31.75 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 Ø31.75 mm drill bit
1) Clean the taper and spindle socket. 2) Check runout (maximum 0.03 mm). 3) Replace the drill if the taper is damaged or worn. 4) Do not stack reduction sleeves (e.g., MT4→MT3→MT5).
For diameters up to approximately 40 mm, drilling into solid material is possible after spot drilling with an NC 90° drill. Above 40 mm, a Ø20–25 mm pilot hole is recommended to reduce axial force by 40–50% and eliminate vibration from the chisel edge.
When drilling S355 steel with a Ø31.75 mm drill, the torque is approximately 79 Nm. This requires a drilling machine with a minimum power rating of 1.9 kW and power spindle feed.
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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