Sutton D109S2 21 Piece Cobalt Imperial Jobber Drill Set - Colour Temp

$407.68

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The Sutton D109S2 is a 21 piece imperial cobalt jobber drill set of D109 heavy duty cobalt jobber drills, 1/16 to 3/8 in in 1/64 in steps, supplied in an ABS case. The drills are made from 5% cobalt high speed steel (HSS-Co) with a colour temp finish, 25° right-hand helix flutes (R25) and a 135° point, and are made to DIN 338.

The D109 is a heavy duty design for hard materials up to 850 N/mm². The self-centring 135° point is a Form C split point on drills above 3/32 in (2.5 mm and larger in metric sizes) and a standard 135° point on smaller sizes. The cobalt content gives high abrasion resistance, and the thick core adds rigidity in hard materials. Each drill in the set is a D109 item, so single replacement drills can be ordered by the item number in the contents table.

What is in the set

The set contains 21 drills in an ABS case: 1/16 to 3/8 in in 1/64 in steps. Flute length (l2) and overall length (l1) are in millimetres.

Piece	Drill size	Replacement item no.	Flute length l2 (mm)	Overall length l1 (mm)
1	1/16 in (1.59 mm)	D109 0159	20	43
2	5/64 in (1.98 mm)	D109 0198	24	49
3	3/32 in (2.38 mm)	D109 0238	30	57
4	7/64 in (2.78 mm)	D109 0278	33	61
5	1/8 in (3.18 mm)	D109 0318	36	65
6	9/64 in (3.57 mm)	D109 0357	39	70
7	5/32 in (3.97 mm)	D109 0397	43	75
8	11/64 in (4.37 mm)	D109 0437	47	80
9	3/16 in (4.76 mm)	D109 0476	52	86
10	13/64 in (5.16 mm)	D109 0516	52	86
11	7/32 in (5.56 mm)	D109 0556	57	93
12	15/64 in (5.95 mm)	D109 0595	57	93
13	1/4 in (6.35 mm)	D109 0635	63	101
14	17/64 in (6.75 mm)	D109 0676	69	109
15	9/32 in (7.14 mm)	D109 0714	69	109
16	19/64 in (7.54 mm)	D109 0754	75	117
17	5/16 in (7.94 mm)	D109 0794	75	117
18	21/64 in (8.33 mm)	D109 0833	75	117
19	11/32 in (8.73 mm)	D109 0873	81	125
20	23/64 in (9.13 mm)	D109 0913	81	125
21	3/8 in (9.52 mm)	D109 0953	87	133

Where this product is used

General drilling in hard materials up to 850 N/mm², using heavy duty cobalt drills.
Machine drilling on a drill press, mill or lathe, and hand-held drilling where the application allows.
Workshop, maintenance and trade kit: one case covering 1.59 to 9.53 mm.
Materials rated Optimal for this drill: brass.
Also rated Effective: high-alloy and tool steels; austenitic stainless steel; duplex stainless steel; grey cast iron; nodular cast iron; malleable cast iron; hardened steel (45 HRC); and chilled cast iron.
Rated Optimal for some grades and Effective for others: non-alloy steels; and low-alloy steels.

Finish

The colour temp finish is a colour-tempered surface that identifies the tool as cobalt high speed steel. The 5% cobalt content improves abrasion and heat resistance for increased strength at higher cutting temperatures.

Cutting speeds and feeds

Cutting speeds (Vc) and feed numbers for the D109 come from the Sutton Application Guide, which covers 13 material groups for this drill. The guide prints the rating as Optimal or Effective, and the table keeps that 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 0.45 %C, quenched and tempered	Optimal	15	5	795 rpm / 0.125 mm/rev	475 rpm / 0.19 mm/rev
Non-alloy steel, about 0.75 %C, annealed	Effective	15	5	795 rpm / 0.125 mm/rev	475 rpm / 0.19 mm/rev
Low-alloy steel, quenched and tempered (275 HB)	Optimal	15	4	795 rpm / 0.1 mm/rev	475 rpm / 0.16 mm/rev
High-alloy and tool steel, annealed	Effective	12	4	635 rpm / 0.1 mm/rev	380 rpm / 0.16 mm/rev
Austenitic stainless steel	Effective	10	4	530 rpm / 0.1 mm/rev	320 rpm / 0.16 mm/rev
Duplex stainless steel	Effective	8	4	425 rpm / 0.1 mm/rev	255 rpm / 0.16 mm/rev
Grey cast iron, ferritic / pearlitic	Effective	25	6	1,330 rpm / 0.16 mm/rev	795 rpm / 0.24 mm/rev
Grey cast iron, pearlitic	Effective	20	5	1,060 rpm / 0.125 mm/rev	635 rpm / 0.19 mm/rev
Nodular cast iron, ferritic	Effective	20	6	1,060 rpm / 0.16 mm/rev	635 rpm / 0.24 mm/rev
Malleable cast iron, ferritic	Effective	20	6	1,060 rpm / 0.16 mm/rev	635 rpm / 0.24 mm/rev
Brass (CuZn, CuSnZn)	Optimal	25	6	1,330 rpm / 0.16 mm/rev	795 rpm / 0.24 mm/rev
Hardened steel, 45 HRC	Effective	10	4	530 rpm / 0.1 mm/rev	320 rpm / 0.16 mm/rev
Chilled cast iron	Effective	20	5	1,060 rpm / 0.125 mm/rev	635 rpm / 0.19 mm/rev

Feed rates (mm/rev) for the feed numbers above:

Ø (mm)	Feed no. 4 (mm/rev)	Feed no. 5 (mm/rev)	Feed no. 6 (mm/rev)
2	0.04	0.05	0.06
3	0.055	0.07	0.09
4	0.075	0.09	0.12
5	0.09	0.11	0.14
6	0.1	0.12	0.16
8	0.13	0.16	0.2
10	0.16	0.19	0.24
12	0.18	0.23	0.28
16	0.23	0.29	0.36
20	0.28	0.34	0.42
25	0.33	0.41	0.5
32	0.41	0.5	0.6
38	0.46	0.56	0.68
45	0.52	0.64	0.76
52	0.58	0.7	0.84
63	0.67	0.8	0.96

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 D109 drill diameter (d) is made to h8: the drill may be at nominal diameter or smaller, never larger.

Drill diameter (mm)	h8 tolerance (minus only, ISO 286-2)
0.2 to 3	14 µm
3 to 6	18 µm
6 to 10	22 µm
10 to 18	27 µm
18 to 30	33 µm
30 to 50	39 µm

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

Specification	Detail
Set number	D109S2
Catalogue code	D109 (Heavy Duty Cobalt Jobber Drill)
Pieces	21
Sizes	1/16 to 3/8 in in 1/64 in steps
Case	ABS
Material	High Speed Steel Cobalt (HSS Co, 5% cobalt)
Finish	Colour temp
Flute geometry	25° right-hand helix (R25)
Point	135° Form C split point on drills above 3/32 in; standard 135° point on smaller sizes
Standard	DIN 338
Diameter tolerance (d)	h8

Related drilling products

Compare other Sutton drills: D109 cobalt jobber drill (bulk pack), D163 DHJ cobalt jobber and D175 spotting drill set. Browse all Imperial Jobber Drill 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.

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