Durable Mills solid carbide micro drill for precision deep hole drilling from 5D to 30D

Precision chisel edge thinning and m7 cutting edge of solid carbide micro drill bit

Solid Carbide Micro Drill for Deep Hole Machining (5D–30D)

Engineered for high-efficiency deep-hole machining, our high-precision solid carbide micro drill series provides superior self-centering capability and smooth chip clearance. This premium solid carbide micro drill line ensures stable dimensional tolerance across stainless steel, alloy steel, and cast iron. Durable Mills supplies high-wear carbide micro drills for industrial CNC production.

12xD

16xD

20xD

25xD

30xD

5xD

8xD

DIN6535HA h6

He/PT

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High-Performance Solid Carbide Micro Drill Bits

Engineered and manufactured by Durable Mills, this premium solid carbide micro drill series is dedicated to ultra-precise micro-hole and deep-hole drilling operations. Covering aspect ratios from 5D up to 30D with cutting diameters ranging from 1.0 mm to 2.9 mm, these micro drill tools deliver supreme dimensional stability, ultra-high surface quality, and reliable tool life in demanding CNC environments.

Key Engineering Characteristics & Specifications

Cutting Edge Tolerance: m7 standard for micro-level accuracy and repeatable hole sizing.
Shank Execution: DIN6535HA h6 precision shank (3.0 mm uniform shank diameter) for minimal runout and rigid hydraulic/shrink-fit clamping.
Flute Geometry: Specially engineered parabolic chip flutes for smooth chip evacuation and reduced risk of chip jamming in deep micro drilling.
Point & Chisel Edge: Proprietary chisel edge thinning and correction providing robust self-centering performance, reducing axial cutting forces and drill wander.
Advanced PVD Coating: Specialized Heat-resistant / High-lubricity nano-coating (He/PT) for superior oxidation threshold and minimal micro-welding on drill margins.

Material Applications

Optimized for high-mix production and batch machining across diverse engineering materials:

Gray Cast Iron & Ductile Iron
Austenitic & Martensitic Stainless Steels (304, 316, 420, etc.)
Structural Steels, Carbon Steels & Pre-hardened Steels
Alloy Steels, Tool Steels & High-Temperature Alloys

Comprehensive Product Specifications

5D Series Micro Drills (Shank: 3.0mm h6)

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	14	17	35	3	57
2.1	14	18	35	3	57
2.2	15	19	34	3	57
2.3	16	20	35	3	59
2.4	16	20	35	3	59
2.5	17	21	34	3	59
2.6	18	22	36	3	62
2.7	18	23	36	3	62
2.8	19	24	35	3	62
2.9	20	25	34	3	62

8D Series Micro Drills (Shank: 3.0mm h6)

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
1.0	12	15	36	3	55
1.1	12	15	36	3	55
1.2	12	15	35	3	55
1.3	12	15	34	3	55
1.4	12	15	33	3	55
1.5	17	20	46	3	68
1.6	17	20	45	3	68
1.7	17	20	44	3	68
1.8	17	20	44	3	68
1.9	17	20	43	3	68
2.0	20	23	35	3	63
2.1	20	24	35	3	63
2.2	21	25	34	3	63
2.3	22	26	37	3	67
2.4	24	28	35	3	67
2.5	25	29	34	3	67
2.6	26	30	37	3	71
2.7	26	31	37	3	71
2.8	27	32	36	3	71
2.9	28	33	35	3	71

12D Series Micro Drills (Shank: 3.0mm h6)

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	28	31	36	3	72
2.1	29	33	35	3	72
2.2	30	34	34	3	72
2.3	32	36	37	3	77
2.4	33	37	36	3	77
2.5	35	39	34	3	77
2.6	36	40	39	3	83
2.7	37	42	38	3	83
2.8	38	43	37	3	83
2.9	40	45	35	3	83

16D Series Micro Drills (Shank: 3.0mm h6)

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	36	39	37	3	81
2.1	37	41	36	3	81
2.2	39	43	34	3	81
2.3	39	45	38	3	87
2.4	43	47	36	3	87
2.5	45	49	34	3	87
2.6	47	51	40	3	95
2.7	48	53	39	3	95
2.8	50	55	37	3	95
2.9	52	57	35	3	95

20D Series Micro Drills (Shank: 3.0mm h6)

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	44	47	38	3	90
2.1	45	49	37	3	90
2.2	48	52	34	3	90
2.3	50	54	39	3	97
2.4	52	56	37	3	97
2.5	55	59	34	3	97
2.6	57	61	42	3	107
2.7	58	63	41	3	107
2.8	61	66	38	3	107
2.9	63	68	36	3	107

25D Series Micro Drills (Shank: 3.0mm h6)

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	54	57	39	3	101
2.1	56	60	37	3	101
2.2	59	63	34	3	101
2.3	62	66	37	3	107
2.4	64	68	35	3	107
2.5	67	71	32	3	107
2.6	70	74	44	3	122
2.7	72	77	41	3	122
2.8	75	80	38	3	122
2.9	78	83	36	3	122

30D Series Micro Drills (Shank: 3.0mm h6)

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	64	67	40	3	112
2.1	66	70	38	3	112
2.2	70	74	34	3	112
2.3	73	74	41	3	112
2.4	76	80	38	3	122
2.5	80	84	34	3	122
2.6	83	87	45	3	136
2.7	85	90	42	3	136
2.8	89	94	38	3	136
2.9	92	97	36	3	136

Frequently Asked Questions (FAQ)

Q1: Is a pilot hole required when drilling deep holes with 16D, 20D, 25D, or 30D micro drills?

Yes, for micro deep-hole drilling above 12D, it is strongly advised to machine a pilot hole using a 1D–3D pilot micro drill of identical or +0.02mm diameter. This ensures correct lead-in guidance and prevents micro-drill deflection or breakage.

Q2: What runout tolerance is recommended for high-precision micro drilling?

We recommend a total indicated runout (TIR) within 0.003 mm (≤ 3 μm) at the tool tip, paired with high-precision collet chucks, shrink-fit chucks, or hydraulic toolholders.

Q3: Can Durable Mills provide custom sizes or OEM batch production?

Absolutely. Durable Mills supports bespoke geometries, step micro-drills, proprietary coating choices, and custom overall lengths for volume B2B procurement.

Q4: How can I request technical data sheets or a bulk quotation?

You can reach our application engineering team directly via Contact Us or email your drawing specifications to info@durablemills.com.

Categories Solid Carbide Drills, Micro Drills Tags 5D-30D Deep Hole Drills, Carbide Small Diameter Drill, CNC Micro Drilling Tools, DIN6535HA Micro Drill, Industrial Micro Drill Bits Wholesale, m7 Tolerance Drill Bits, Micro Deep Hole Drill, Miniature Twist Drill, OEM carbide cutting tools supplier, Precision Micro Drill Bits, Solid Carbide Micro Drill, Stainless Steel Micro Drilling Brand: Durable Mills

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	14	17	35	3	57
2.1	14	18	35	3	57
2.2	15	19	34	3	57
2.3	16	20	35	3	59
2.4	16	20	35	3	59
2.5	17	21	34	3	59
2.6	18	22	36	3	62
2.7	18	23	36	3	62
2.8	19	24	35	3	62
2.9	20	25	34	3	62

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
1.0	12	15	36	3	55
1.1	12	15	36	3	55
1.2	12	15	35	3	55
1.3	12	15	34	3	55
1.4	12	15	33	3	55
1.5	17	20	46	3	68
1.6	17	20	45	3	68
1.7	17	20	44	3	68
1.8	17	20	44	3	68
1.9	17	20	43	3	68
2.0	20	23	35	3	63
2.1	20	24	35	3	63
2.2	21	25	34	3	63
2.3	22	26	37	3	67
2.4	24	28	35	3	67
2.5	25	29	34	3	67
2.6	26	30	37	3	71
2.7	26	31	37	3	71
2.8	27	32	36	3	71
2.9	28	33	35	3	71

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	28	31	36	3	72
2.1	29	33	35	3	72
2.2	30	34	34	3	72
2.3	32	36	37	3	77
2.4	33	37	36	3	77
2.5	35	39	34	3	77
2.6	36	40	39	3	83
2.7	37	42	38	3	83
2.8	38	43	37	3	83
2.9	40	45	35	3	83

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	36	39	37	3	81
2.1	37	41	36	3	81
2.2	39	43	34	3	81
2.3	39	45	38	3	87
2.4	43	47	36	3	87
2.5	45	49	34	3	87
2.6	47	51	40	3	95
2.7	48	53	39	3	95
2.8	50	55	37	3	95
2.9	52	57	35	3	95

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	44	47	38	3	90
2.1	45	49	37	3	90
2.2	48	52	34	3	90
2.3	50	54	39	3	97
2.4	52	56	37	3	97
2.5	55	59	34	3	97
2.6	57	61	42	3	107
2.7	58	63	41	3	107
2.8	61	66	38	3	107
2.9	63	68	36	3	107

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	54	57	39	3	101
2.1	56	60	37	3	101
2.2	59	63	34	3	101
2.3	62	66	37	3	107
2.4	64	68	35	3	107
2.5	67	71	32	3	107
2.6	70	74	44	3	122
2.7	72	77	41	3	122
2.8	75	80	38	3	122
2.9	78	83	36	3	122

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	64	67	40	3	112
2.1	66	70	38	3	112
2.2	70	74	34	3	112
2.3	73	74	41	3	112
2.4	76	80	38	3	122
2.5	80	84	34	3	122
2.6	83	87	45	3	136
2.7	85	90	42	3	136
2.8	89	94	38	3	136
2.9	92	97	36	3	136

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	14	17	35	3	57
2.1	14	18	35	3	57
2.2	15	19	34	3	57
2.3	16	20	35	3	59
2.4	16	20	35	3	59
2.5	17	21	34	3	59
2.6	18	22	36	3	62
2.7	18	23	36	3	62
2.8	19	24	35	3	62
2.9	20	25	34	3	62

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
1.0	12	15	36	3	55
1.1	12	15	36	3	55
1.2	12	15	35	3	55
1.3	12	15	34	3	55
1.4	12	15	33	3	55
1.5	17	20	46	3	68
1.6	17	20	45	3	68
1.7	17	20	44	3	68
1.8	17	20	44	3	68
1.9	17	20	43	3	68
2.0	20	23	35	3	63
2.1	20	24	35	3	63
2.2	21	25	34	3	63
2.3	22	26	37	3	67
2.4	24	28	35	3	67
2.5	25	29	34	3	67
2.6	26	30	37	3	71
2.7	26	31	37	3	71
2.8	27	32	36	3	71
2.9	28	33	35	3	71

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	28	31	36	3	72
2.1	29	33	35	3	72
2.2	30	34	34	3	72
2.3	32	36	37	3	77
2.4	33	37	36	3	77
2.5	35	39	34	3	77
2.6	36	40	39	3	83
2.7	37	42	38	3	83
2.8	38	43	37	3	83
2.9	40	45	35	3	83

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	36	39	37	3	81
2.1	37	41	36	3	81
2.2	39	43	34	3	81
2.3	39	45	38	3	87
2.4	43	47	36	3	87
2.5	45	49	34	3	87
2.6	47	51	40	3	95
2.7	48	53	39	3	95
2.8	50	55	37	3	95
2.9	52	57	35	3	95

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	44	47	38	3	90
2.1	45	49	37	3	90
2.2	48	52	34	3	90
2.3	50	54	39	3	97
2.4	52	56	37	3	97
2.5	55	59	34	3	97
2.6	57	61	42	3	107
2.7	58	63	41	3	107
2.8	61	66	38	3	107
2.9	63	68	36	3	107

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	54	57	39	3	101
2.1	56	60	37	3	101
2.2	59	63	34	3	101
2.3	62	66	37	3	107
2.4	64	68	35	3	107
2.5	67	71	32	3	107
2.6	70	74	44	3	122
2.7	72	77	41	3	122
2.8	75	80	38	3	122
2.9	78	83	36	3	122

Diameter D (mm)	Effective Depth L4 (mm)	Flute Length L3 (mm)	Shank Length LS (mm)	Shank Dia. d (mm)	Overall Length L (mm)
2.0	64	67	40	3	112
2.1	66	70	38	3	112
2.2	70	74	34	3	112
2.3	73	74	41	3	112
2.4	76	80	38	3	122
2.5	80	84	34	3	122
2.6	83	87	45	3	136
2.7	85	90	42	3	136
2.8	89	94	38	3	136
2.9	92	97	36	3	136