Sutton D371 0780 7.8mm 12xD Solid Carbide Drill, AlCrN tip, Internal Coolant
Available
The Sutton D371 is a 12xD solid carbide (VHM) drill with internal coolant supply, a 30° right-hand helix (R30) and a 135° Form C point. It carries an AlCrN tip coating, has an HA shank to DIN 6535 and is for materials up to 1200 N/mm². This range has 83 sizes from 3 to 12 mm.
The strong core and the micro geometry and surface conditioning are designed for optimal chip control, and the internal coolant supply carries coolant to the cutting edges through the drill. The AlCrN tip finish is designed for maximum tool life. The drill diameter (d1) tolerance is m7 and the shank diameter (d2) tolerance is h6. At 12xD this is the long-reach drill in the carbide internal-coolant family, for deeper holes than the 3xD to 8xD drills.
Where this product is used
- Deep-hole drilling to 12 × Ø with internal coolant, in toolroom, machine shop, production, maintenance and fabrication work.
- Materials up to 1200 N/mm², including steels, stainless steels and cast irons, with the material groups rated in the speed table below.
- Rated Optimal in the application guide: non-alloy steels; low-alloy steels; high-alloy and tool steels.
- Rated Effective: austenitic stainless steel; duplex stainless steel; malleable cast iron; chilled and hardened cast iron.
- Rated Optimal for some grades and Effective for others: grey cast iron; nodular cast iron.
- Hole depths to 12 × Ø. Step feeding or pecking is required beyond 3 × Ø.
Design features
- 12xD solid carbide drill with internal coolant supply.
- Strong core with micro geometry and surface conditioning for optimal chip control.
- AlCrN tip for maximum tool life.
- R30: 30° right-hand helix.
- 135° Form C point.
- HA shank to DIN 6535; d1 tolerance m7, d2 tolerance h6.
- For materials up to 1200 N/mm².
- 83 sizes from 3 to 12 mm.
Finish
AlCrN (aluminium chromium nitride) tip coating. AlCrN has a microhardness of 3200 HV and thermal stability up to about 1100 °C (2012 °F). It suits low-alloy and high-tensile steels, hardened steels up to 54 HRC, high-speed machining, and minimum quantity lubrication (MQL) or dry machining.
Sizes and item numbers
Every size in this range, with its Sutton item number. The inch column shows the fractional equivalent where the size has one. Lengths are in millimetres.
| Item no. | Ø d1 (mm) | Ø (in) | Overall length l1 (mm) | Flute length l2 (mm) | Shank d2 (mm) |
|---|---|---|---|---|---|
| D371 0300 | 3 | - | 90 | 50 | 6 |
| D371 0310 | 3.1 | - | 90 | 50 | 6 |
| D371 0320 | 3.2 | - | 90 | 50 | 6 |
| D371 0330 | 3.3 | - | 90 | 50 | 6 |
| D371 0350 | 3.5 | - | 90 | 50 | 6 |
| D371 0360 | 3.6 | - | 90 | 50 | 6 |
| D371 0370 | 3.7 | - | 90 | 50 | 6 |
| D371 0380 | 3.8 | - | 102 | 64 | 6 |
| D371 0390 | 3.9 | - | 102 | 64 | 6 |
| D371 0400 | 4 | - | 102 | 64 | 6 |
| D371 0410 | 4.1 | - | 102 | 64 | 6 |
| D371 0420 | 4.2 | - | 102 | 64 | 6 |
| D371 0430 | 4.3 | - | 102 | 64 | 6 |
| D371 0440 | 4.4 | - | 102 | 64 | 6 |
| D371 0450 | 4.5 | - | 102 | 64 | 6 |
| D371 0460 | 4.6 | - | 102 | 64 | 6 |
| D371 0470 | 4.7 | - | 102 | 64 | 6 |
| D371 0480 | 4.8 | - | 116 | 78 | 6 |
| D371 0490 | 4.9 | - | 116 | 78 | 6 |
| D371 0500 | 5 | - | 116 | 78 | 6 |
| D371 0510 | 5.1 | - | 116 | 78 | 6 |
| D371 0520 | 5.2 | - | 116 | 78 | 6 |
| D371 0530 | 5.3 | - | 116 | 78 | 6 |
| D371 0540 | 5.4 | - | 116 | 78 | 6 |
| D371 0550 | 5.5 | - | 116 | 78 | 6 |
| D371 0560 | 5.6 | - | 116 | 78 | 6 |
| D371 0570 | 5.7 | - | 116 | 78 | 6 |
| D371 0580 | 5.8 | - | 116 | 78 | 6 |
| D371 0590 | 5.9 | - | 116 | 78 | 6 |
| D371 0600 | 6 | - | 116 | 78 | 6 |
| D371 0610 | 6.1 | - | 146 | 108 | 8 |
| D371 0620 | 6.2 | - | 146 | 108 | 8 |
| D371 0630 | 6.3 | - | 146 | 108 | 8 |
| D371 0640 | 6.4 | - | 146 | 108 | 8 |
| D371 0650 | 6.5 | - | 146 | 108 | 8 |
| D371 0660 | 6.6 | - | 146 | 108 | 8 |
| D371 0670 | 6.7 | - | 146 | 108 | 8 |
| D371 0680 | 6.8 | - | 146 | 108 | 8 |
| D371 0690 | 6.9 | - | 146 | 108 | 8 |
| D371 0700 | 7 | - | 146 | 108 | 8 |
| D371 0710 | 7.1 | - | 146 | 108 | 8 |
| D371 0720 | 7.2 | - | 146 | 108 | 8 |
| D371 0730 | 7.3 | - | 146 | 108 | 8 |
| D371 0740 | 7.4 | - | 146 | 108 | 8 |
| D371 0750 | 7.5 | - | 146 | 108 | 8 |
| D371 0760 | 7.6 | - | 146 | 108 | 8 |
| D371 0770 | 7.7 | - | 146 | 108 | 8 |
| D371 0780 | 7.8 | - | 146 | 108 | 8 |
| D371 0790 | 7.9 | - | 146 | 108 | 8 |
| D371 0800 | 8 | - | 146 | 108 | 8 |
| D371 0810 | 8.1 | - | 162 | 120 | 10 |
| D371 0820 | 8.2 | - | 162 | 120 | 10 |
| D371 0830 | 8.3 | - | 162 | 120 | 10 |
| D371 0840 | 8.4 | - | 162 | 120 | 10 |
| D371 0850 | 8.5 | - | 162 | 120 | 10 |
| D371 0860 | 8.6 | - | 162 | 120 | 10 |
| D371 0870 | 8.7 | - | 162 | 120 | 10 |
| D371 0880 | 8.8 | - | 162 | 120 | 10 |
| D371 0890 | 8.9 | - | 162 | 120 | 10 |
| D371 0900 | 9 | - | 162 | 120 | 10 |
| D371 0910 | 9.1 | - | 162 | 120 | 10 |
| D371 0920 | 9.2 | - | 162 | 120 | 10 |
| D371 0930 | 9.3 | - | 162 | 120 | 10 |
| D371 0940 | 9.4 | - | 162 | 120 | 10 |
| D371 0950 | 9.5 | - | 162 | 120 | 10 |
| D371 0960 | 9.6 | - | 162 | 120 | 10 |
| D371 0970 | 9.7 | - | 162 | 120 | 10 |
| D371 0980 | 9.8 | - | 162 | 120 | 10 |
| D371 0990 | 9.9 | - | 162 | 120 | 10 |
| D371 1000 | 10 | - | 162 | 120 | 10 |
| D371 1010 | 10.1 | - | 204 | 156 | 12 |
| D371 1020 | 10.2 | - | 204 | 156 | 12 |
| D371 1030 | 10.3 | - | 204 | 156 | 12 |
| D371 1040 | 10.4 | - | 204 | 156 | 12 |
| D371 1050 | 10.5 | - | 204 | 156 | 12 |
| D371 1060 | 10.6 | - | 204 | 156 | 12 |
| D371 1080 | 10.8 | - | 204 | 156 | 12 |
| D371 1090 | 10.9 | - | 204 | 156 | 12 |
| D371 1100 | 11 | - | 204 | 156 | 12 |
| D371 1110 | 11.1 | - | 204 | 156 | 12 |
| D371 1150 | 11.5 | - | 204 | 156 | 12 |
| D371 1160 | 11.6 | - | 204 | 156 | 12 |
| D371 1200 | 12 | - | 204 | 156 | 12 |
Cutting speeds and feeds
The application guide gives cutting speeds (Vc) and feed numbers for this drill, with Optimal ratings in bold and Effective ratings in regular type; the Rating column shows the same split. The rpm and feed columns show what the speed and feed number work out to at Ø6 mm and Ø10 mm (speed in rpm = Vc × 1000 ÷ (π × Ø)). Treat these as starting values and adjust for the machine, set-up and coolant.
| Material (VDI 3323 group) | Rating | Vc (m/min) | Feed no. | Ø6 mm: rpm / feed | Ø10 mm: rpm / feed |
|---|---|---|---|---|---|
| Non-alloy steel, about 0.15 %C, annealed (125 HB) | Optimal | 80 | 8 | 4,240 rpm / 0.24 mm/rev | 2,550 rpm / 0.37 mm/rev |
| Non-alloy steel, about 0.45 %C, annealed (190 HB) | Optimal | 80 | 8 | 4,240 rpm / 0.24 mm/rev | 2,550 rpm / 0.37 mm/rev |
| Non-alloy steel, about 0.45 %C, quenched and tempered (250 HB) | Optimal | 60 | 7 | 3,180 rpm / 0.19 mm/rev | 1,910 rpm / 0.3 mm/rev |
| Non-alloy steel, about 0.75 %C, annealed (270 HB) | Optimal | 60 | 7 | 3,180 rpm / 0.19 mm/rev | 1,910 rpm / 0.3 mm/rev |
| Non-alloy steel, about 0.75 %C, quenched and tempered (300 HB) | Optimal | 50 | 6 | 2,650 rpm / 0.16 mm/rev | 1,590 rpm / 0.24 mm/rev |
| Low-alloy and cast steel (under 5% alloying), annealed (180 HB) | Optimal | 60 | 7 | 3,180 rpm / 0.19 mm/rev | 1,910 rpm / 0.3 mm/rev |
| Low-alloy steel, quenched and tempered (275 HB) | Optimal | 60 | 7 | 3,180 rpm / 0.19 mm/rev | 1,910 rpm / 0.3 mm/rev |
| Low-alloy steel, quenched and tempered (300 HB) | Optimal | 50 | 6 | 2,650 rpm / 0.16 mm/rev | 1,590 rpm / 0.24 mm/rev |
| High-alloy, cast and tool steel, annealed (200 HB) | Optimal | 50 | 6 | 2,650 rpm / 0.16 mm/rev | 1,590 rpm / 0.24 mm/rev |
| Austenitic stainless steel, age hardened (180 HB) | Effective | 40 | 5 | 2,120 rpm / 0.12 mm/rev | 1,270 rpm / 0.19 mm/rev |
| Duplex stainless steel (250 HB) | Effective | 30 | 4 | 1,590 rpm / 0.1 mm/rev | 955 rpm / 0.16 mm/rev |
| Grey cast iron, ferritic / pearlitic (180 HB) | Optimal | 80 | 8 | 4,240 rpm / 0.24 mm/rev | 2,550 rpm / 0.37 mm/rev |
| Grey cast iron, pearlitic (260 HB) | Effective | 70 | 8 | 3,710 rpm / 0.24 mm/rev | 2,230 rpm / 0.37 mm/rev |
| Nodular cast iron, ferritic (160 HB) | Optimal | 60 | 7 | 3,180 rpm / 0.19 mm/rev | 1,910 rpm / 0.3 mm/rev |
| Nodular cast iron, pearlitic (250 HB) | Effective | 60 | 7 | 3,180 rpm / 0.19 mm/rev | 1,910 rpm / 0.3 mm/rev |
| Malleable cast iron, ferritic (130 HB) | Effective | 60 | 7 | 3,180 rpm / 0.19 mm/rev | 1,910 rpm / 0.3 mm/rev |
| Malleable cast iron, pearlitic (230 HB) | Effective | 60 | 7 | 3,180 rpm / 0.19 mm/rev | 1,910 rpm / 0.3 mm/rev |
| Chilled cast iron (400 HB) | Effective | 70 | 8 | 3,710 rpm / 0.24 mm/rev | 2,230 rpm / 0.37 mm/rev |
Feed rates (mm/rev) for the feed numbers above, by drill diameter:
| Ø (mm) | Feed no. 4 (mm/rev) | Feed no. 5 (mm/rev) | Feed no. 6 (mm/rev) | Feed no. 7 (mm/rev) | Feed no. 8 (mm/rev) |
|---|---|---|---|---|---|
| 2 | 0.04 | 0.05 | 0.06 | 0.075 | 0.095 |
| 3 | 0.055 | 0.07 | 0.09 | 0.11 | 0.135 |
| 4 | 0.075 | 0.09 | 0.115 | 0.14 | 0.18 |
| 5 | 0.09 | 0.11 | 0.135 | 0.17 | 0.21 |
| 6 | 0.1 | 0.125 | 0.16 | 0.19 | 0.24 |
| 8 | 0.13 | 0.16 | 0.2 | 0.25 | 0.31 |
| 10 | 0.16 | 0.19 | 0.24 | 0.3 | 0.37 |
| 12 | 0.18 | 0.23 | 0.28 | 0.34 | 0.42 |
Drilling notes
- Step feeding or pecking is required for drilling greater than 3 x Ø.
- When drilling a cast or black (not machined) surface, reduce the drilling speed by 20%.
- For optimal positional accuracy and hole size, the use of spot drills is recommended prior to drilling the desired hole; see Sutton's spotting drill range (D175).
- For hole depths greater than 7 x Ø, pre-drill a pilot hole first for more accurate hole position and to stop the drill wandering. The pilot can be drilled with a short, rigid drill about 3 x Ø deep at reduced feed.
Accuracy
The drill diameter (d1) tolerance is m7 and the shank diameter (d2) tolerance is h6.
Key specifications
| Specification | Detail |
|---|---|
| Catalogue code | D371 (12xD solid carbide drill, internal coolant) |
| Type | Solid carbide drill bit, IK internal coolant |
| Material | Solid carbide (VHM) |
| Finish | AlCrN (aluminium chromium nitride) tip coating |
| Flute geometry | R30: 30° right-hand helix |
| Point | 135° Form C |
| Shank | HA, DIN 6535 plain cylindrical |
| Drill diameter tolerance (d1) | m7 |
| Shank tolerance (d2) | h6 |
| Drilling depth | up to 12 × Ø |
| Suitable for materials | up to 1200 N/mm² |
| Sizes in this range | 83 sizes, 3 to 12 mm |
Related drilling products
Compare other Sutton solid carbide drills: D335 8xD, D332 5xD through-coolant and D329 3xD through-coolant. Browse all carbide drill bits. Need help choosing? Our drilling guides cover drill types and materials.
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Sutton D371 12xD Solid Carbide Drill with Internal Coolant, AlCrN Tip, 3 to 12mm: 7.8
SKU: A0130737 | Model: D3710780
This is the 7.8mm diameter option of the Sutton D371 12xD Solid Carbide Drill with Internal Coolant, AlCrN Tip, 3 to 12mm. Key details for this option: flute length 108mm, overall length 146mm.