Sutton 2mm D171 DHL Long Series Drill Bit - Metric - Cobalt TiAlN

The Sutton D171 is a DHL long series drill (designation NH) made from 5% cobalt high speed steel (HSS-Co) with a TiAlN coating. It has 40° right-hand helix flutes (R40), a 130° Form B point (130° 4 facet point on sizes under 3.0 mm) and a straight shank, d1 to h8, and is made to DIN 340.

It is a high performance long series drill for materials up to 1200 N/mm². The point geometry is designed for high strength, the parabolic flute design for optimal chip transportation, and it needs less pecking than a standard drill. The TiAlN coating is for longer tool life.

This range has 95 sizes from 1 to 13 mm, with flute lengths of 33 to 134 mm and overall lengths of 56 to 205 mm.

Where this product is used

• Deep holes, where a standard jobber drill is too short; less pecking is required than with a standard drill.
• Materials up to 1200 N/mm².
• Materials rated Optimal for this drill: non-alloy steels; grey cast iron; nodular cast iron; malleable cast iron; aluminium and magnesium cast alloys over 12% Si; and chilled cast iron.
• Also rated Effective: ferritic and martensitic stainless steels; austenitic stainless steel; precipitation-hardening stainless steel; free-cutting copper alloys, brass; and thermosetting and fibre-reinforced plastics.
• Rated Optimal for some grades and Effective for others: low-alloy steels; high-alloy and tool steels; and cast aluminium and magnesium alloys (up to 12% Si).
• Hole depths up to 8 × Ø. Step feeding or pecking is required beyond 3 × Ø.

Finish

Titanium aluminium nitride (TiAlN) has a microhardness of 3300 HV and is stable to about 900 °C (1652 °F). It is used on abrasive and difficult-to-machine materials such as stainless steel, at higher speeds and feeds, and with reduced or no coolant.

Speeds, feeds and deep-hole drilling

The High Performance catalogue application guide does not print a speed and feed table for this long series drill. The D171 uses the same cobalt substrate, TiAlN coating and R40 flute geometry as the Sutton D163 DHJ jobber drill, so the D163 DHJ speed table is a sensible reference. Reduce speed and feed as the hole gets deeper, drill in pecks to clear the flutes, and drill a short pilot hole first for holes deeper than 7 × Ø.

Sizes and item numbers

Every size in the range, with its Sutton item number, flute length (l2) and overall length (l1).

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, use a spot drill before drilling the hole; the Sutton D175 and D176 spotting drills are made for this.
• 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 size table gives the drill diameter (d1) tolerance as h8. An h8 drill diameter may be at nominal or smaller, never larger.

Troubleshooting

• Drill breaks. Dull point: sharpen; Drill has front taper due to wearing: sharpen; Insufficient lip clearance on point: grind correctly; Lip clearance too great: regrind to correct clearance angle.
• Outer corner breaks down. Flutes clogged with chips: remove drill from hole and clear the flutes; Cutting speed too high: reduce speed; Dry cutting, no lubricant at cutting edges: apply cutting fluid.
• Cutting edges chip. Lip clearance too great: regrind to correct clearance angle; Feed too heavy: reduce feed.
• Hole rough. Dull point: sharpen; Feed too heavy: reduce feed; Dry cutting, no lubricant at cutting edges: apply cutting fluid; Fixture/clamping not rigid: secure job firmly.
• Hole oversize. Unequal angle or uneven length of cutting edges: regrind to same lip lengths and angles; Spindle run-out / loose spindle: check machine.

Key specifications

Related drilling products

Compare other Sutton drills: D194 DHXL-1 extra long, D195 DHXL-2 extra long, D196 DHXL-3 extra long and D163 DHJ jobber. Browse all Long Drill Bits. Need help choosing? Our guide to choosing the right drill bit and drill bit selection guide cover drill types and materials, and the speeds and feeds chart and cutting tool troubleshooting guide cover speeds and common problems.