Sutton 3mm D176 120° Spotting Drill Bit - HSS-Co TiN - DIN 1897

The Sutton D176 is a 120° NC spotting drill (designation N) made from 5% cobalt high speed steel (HSS-Co) with a TiN coating. It has a straight shank (shank form A) and is made to DIN 1897. This range has 10 sizes from 3 to 25 mm, with flute lengths of 16 to 37 mm and overall lengths of 49 to 151 mm.

It is a precision drill for machine use. The rigid design is for “seat” position accuracy, and the 120° point suits spotting ahead of a drill because it matches a typical drill point. Only drill to the depth of the point. The 4 piece set is listed separately.

Where this product is used

• Spotting for a drill to follow: the 120° point matches a typical drill point.
• NC and CNC machine drilling, where the position of the hole is set by the spot.
• Starting holes accurately ahead of a drill, in the materials rated below.
• Materials rated Optimal for this drill: austenitic stainless steel; duplex stainless steel; wrought aluminium and magnesium alloys; and cast aluminium and magnesium alloys (up to 12% Si).
• Also rated Effective: annealed high-alloy and tool steel; ferritic and martensitic stainless steels; precipitation-hardening stainless steel; malleable cast iron; aluminium and magnesium cast alloys over 12% Si; thermosetting and fibre-reinforced plastics; Fe-based high-temperature alloys; annealed Ni / Co based high-temperature alloy, age-hardened Ni / Co based high-temperature alloy; titanium alpha alloys, annealed titanium alpha / beta alloys, annealed titanium beta alloys; hardened steel (45 HRC); and chilled cast iron.
• Rated Optimal for some grades and Effective for others: non-alloy steels; low-alloy steels; grey cast iron; nodular cast iron; and copper alloys, brass and bronze.
• Spot only to the depth of the point. Spot depth: see the table below.

Finish

Titanium nitride (TiN) is a single-layer coating with a microhardness of 2300 HV and thermal stability to about 600 °C (1112 °F). It is a general-purpose coating for a wide range of materials, and is designed to give longer tool life than an uncoated tool and allow higher speeds and feeds.

Spot depth

A spotting drill makes a conical spot, so the depth of the spot is set by the point angle. For a 120° point the depth of the cone is spot diameter ÷ 3.46 (calculated from the point angle). The spot can be as large as the diameter of the drill itself.

Sizes and item numbers

Every size in the range, with its Sutton item number, flute length (l2), overall length (l1) and shank diameter (d2). Each item is a single drill.

Drilling notes

• Drill only to the depth of the point.
• For optimal positional accuracy and hole size, spot the hole first; this 120° spotting drill is made for it.
• No separate speed table is published for the spotting drills. Use the D163 DHJ cobalt jobber drill speed table at the same diameter as a sensible reference for starting speed, adjusted for the machine, set-up and coolant.
• For hard or abrasive work where a carbide spotting drill is wanted, see the D365 142° carbide spotting drill.

Accuracy

The size table gives the drill diameter (d1) tolerance as h8 and the shank tolerance as h9. 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: D175 90° spotting drill, D176 4 piece spotting drill set, D365 142° carbide spotting drill, D151 CNC stub drill and D163 DHJ jobber. Browse all Spotting Drill Bit Sets. 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.