What Size Drill Bit For M10-1.50 Bolt

Download PDF of every drill size chart in this article

Every drill size nautical chart y'all'll ever need is in this article! No more scratching your head wondering which guess relates to which size or how to convert inches to mm or vice versa. This is your one-stop-shop for all drill flake size conversions and tables.

Just, there's more than to this commodity than only charts.

You will also get some background on how the various drill sizes came most, how they are calculated and some of their applications. If you've ever wondered why there are so many different gauge designations and drill bit sizes, and so read on.

How to Measure Drill Bits

To measure the diameter of a drill bit, it's best to measure the cutting edge rather than the shank (the shank is the part that is held by the drill chuck). To get an accurate measurement, use Vernier callipers, but be aware that depending on the quality of the drill chip, at that place could be a tolerance error of between five and fifteen thousandths of a unit.

Metric Drill Bit Sizes

Metric drill sizes are used primarily in Europe and use metric units to measure the drill bit diameter. There are a variety of standards used to define drill sizes, the virtually mutual one in the UK is the British Standard BS 328 set up which includes twist drill bit sizes between 0.2 mm and 25 mm.

BS 328 drill sizes are divers as shown in the drill size nautical chart below:

ø0.2 to 0.98 mm:	N. 0.1 mm N. 0.ane + 0.02 mm N. 0.one + 0.05 mm N. 0.1 + 0.08 mm	N is an integer between 2 and 9
ø1.0 to 2.95 mm:	North. 0.1 mm Due north. 0.1 + 0.05 mm	N is an integer betwixt 10 and 29
ø3.0 to 13.9 mm:	Northward. 0.1 mm	N is an integer betwixt 30 and 139
ø14.0 to 25.0 mm:	M. 1mm M. one + 0.25 mm K. ane + 0.5 mm M. 1 + 0.75 mm	M is an integer between 14 to 25

Please annotation that BS 328 sizing only applies to twist drill bits. Other fleck types, such as Forstner bits, will contain dissimilar size cutting surfaces.

Some other example of a metric set up of drill sizes is the Renard series, which uses a simple factor to determine the bore:

The R5 serial uses a cistron of one.58 and contains the following sizes: M2.5, M4, M6, M10, M16 and M24
The R10 series uses a cistron of 1.26 and contains the following sizes: M3, M5, M8, M12, M20 and M30

Drill Size Nautical chart for Number and Letter Gauges

Number and letter gauges exercise not follow a formula or standard increments. They are loosely based on the Stubs Steel Wire Judge, with gauge sizes that are similar (but not entirely identical) to that system.

Although they originated in the 19^thursdaycentury, these gauges are still commonly used in the U.S. They are also seen in the Britain to a lesser degree, having been largely replaced by metric sizes. Most other countries, particularly in Europe, have abandoned them entirely in favour of metric systems.

The drill size nautical chart below contains imperial and metric drill bit diameter measurements for all number and letter gauges.

Guess	inch	mm	Gauge	inch	mm	Gauge	inch	mm
104	0.0031	0.079	52	0.0635	one.613	A	0.234	5.944
103	0.0035	0.089	51	0.067	1.702	B	0.238	6.045
102	0.0039	0.099	50	0.07	one.778	C	0.242	6.147
101	0.0043	0.109	49	0.073	1.854	D	0.246	6.248
100	0.0047	0.119	48	0.076	i.93	East	0.25	6.35
99	0.0051	0.xiii	47	0.0785	ane.994	F	0.257	six.528
98	0.0055	0.fourteen	46	0.081	2.057	G	0.261	six.629
97	0.0059	0.15	45	0.082	2.083	H	0.266	half-dozen.756
96	0.0063	0.sixteen	44	0.086	2.184	I	0.272	6.909
95	0.0067	0.17	43	0.089	ii.261	J	0.277	7.036
94	0.0071	0.eighteen	42	0.0935	ii.375	Chiliad	0.281	seven.137
93	0.0075	0.191	41	0.096	ii.438	50	0.29	7.366
92	0.0079	0.201	40	0.098	2.489	Grand	0.295	7.493
91	0.0083	0.211	39	0.0995	two.527	N	0.302	7.671
90	0.0087	0.221	38	0.1015	ii.578	O	0.316	viii.026
89	0.0091	0.231	37	0.104	2.642	P	0.323	8.204
88	0.0095	0.241	36	0.1065	2.705	Q	0.332	8.433
87	0.01	0.254	35	0.11	2.794	R	0.339	eight.611
86	0.0105	0.267	34	0.111	ii.819	Due south	0.348	8.839
85	0.011	0.279	33	0.113	2.87	T	0.358	9.093
84	0.0115	0.292	32	0.116	two.946	U	0.368	nine.347
83	0.012	0.305	31	0.12	3.048	V	0.377	9.576
82	0.0125	0.318	xxx	0.1285	3.264	W	0.386	ix.804
81	0.013	0.33	29	0.136	three.454	X	0.397	ten.08
fourscore	0.0135	0.343	28	0.1405	iii.569	Y	0.404	ten.26
79	0.0145	0.368	27	0.144	3.658	Z	0.413	x.49
78	0.016	0.406	26	0.147	iii.734	R	0.339	8.611
77	0.018	0.457	25	0.1495	3.797	Due south	0.348	8.839
76	0.02	0.508	24	0.152	3.861	T	0.358	nine.093
75	0.021	0.533	23	0.154	iii.912	U	0.368	9.347
74	0.0225	0.572	22	0.157	3.988	5	0.377	9.576
73	0.024	0.61	21	0.159	4.039
72	0.025	0.635	20	0.161	4.089
71	0.026	0.66	19	0.166	4.216
70	0.028	0.711	18	0.1695	iv.305
69	0.0292	0.742	17	0.173	4.394
68	0.031	0.787	sixteen	0.177	4.496
67	0.032	0.813	15	0.18	4.572
66	0.033	0.838	14	0.182	iv.623
65	0.035	0.889	xiii	0.185	4.699
64	0.036	0.914	12	0.189	4.801
63	0.037	0.94	eleven	0.191	4.851
62	0.038	0.965	10	0.1935	4.915
61	0.039	0.991	nine	0.196	4.978
60	0.04	1.016	8	0.199	v.055
59	0.041	1.041	7	0.201	5.105
58	0.042	ane.067	6	0.204	5.182
57	0.043	one.092	v	0.2055	5.22
56	0.0465	1.181	4	0.209	v.309
55	0.052	1.321	3	0.213	5.41
54	0.055	1.397	two	0.221	v.613
53	0.0595	ane.511	1	0.228	v.791

Fractional-inch Drill Size Chart

Fractional drill bits are definedby the ANSI B94.11M-1979 standard.

Most ordinarily used in the The states, but can still be found occasionally in the Britain, these imperial measurement drill bits come in i/64 inch increments. The fractions used are ever in their simplest form, i.e. reduced as far equally possible, then 2/64 becomes 1/32 for instance.

The drill size nautical chart beneath gives fractional sizes and their metric conversions up to 1 inch.

Fraction of an inch	inch	mm	Fraction of an inch	inch	mm	Fraction of an inch	inch	mm
1/64	0.0156	0.3969	23/64	0.3594	nine.1281	45/64	0.7031	17.8594
i/32	0.0313	0.7938	three/8	0.3750	ix.5250	23/32	0.7188	xviii.2563
iii/64	0.0469	1.1906	25/64	0.3906	9.9219	47/64	0.7344	18.6531
1/16	0.0625	1.5875	13/32	0.4063	10.3188	three/4	0.7500	19.0500
5/64	0.0781	i.9844	27/64	0.4219	10.7156	49/64	0.7656	19.4469
3/32	0.0938	2.3813	7/16	0.4375	11.1125	25/32	0.7813	xix.8438
7/64	0.1094	ii.7781	29/64	0.4531	11.5094	51/64	0.7969	20.2406
1/8	0.1250	three.1750	fifteen/32	0.4688	11.9063	thirteen/sixteen	0.8125	20.6375
ix/64	0.1406	3.5719	31/64	0.4844	12.3031	53/64	0.8281	21.0344
five/32	0.1563	3.9688	1/2	0.5000	12.7000	27/32	0.8438	21.4313
11/64	0.1719	4.3656	33/64	0.5156	13.0969	55/64	0.8594	21.8281
3/16	0.1875	4.7625	17/32	0.5313	13.4938	seven/viii	0.8750	22.2250
13/64	0.2031	5.1594	35/64	0.5469	13.8906	57/64	0.8906	22.6219
7/32	0.2188	5.5563	9/16	0.5625	xiv.2875	29/32	0.9063	23.0188
15/64	0.2344	5.9531	37/64	0.5781	xiv.6844	59/64	0.9219	23.4156
ane/4	0.2500	vi.3500	nineteen/32	0.5938	15.0813	15/16	0.9375	23.8125
17/64	0.2656	6.7469	39/64	0.6094	15.4781	61/64	0.9531	24.2094
9/32	0.2813	seven.1438	5/8	0.6250	15.8750	31/32	0.9688	24.6063
19/64	0.2969	vii.5406	41/64	0.6406	16.2719	63/64	0.9844	25.0031
5/16	0.3125	vii.9375	21/32	0.6563	xvi.6688	1	1.0000	25.4000
21/64	0.3281	8.3344	43/64	0.6719	17.0656
eleven/32	0.3438	8.7313	xi/16	0.6875	17.4625

Heart Drill Bit Sizes

These specialist drill bits are used for drilling centre holes at ii different angles, lx degrees and 90 degrees. They are commonly used to drill lathe centres and spotting drills, i.e.marking holes to guide twist drilling.

The drill size chart beneath contains all commonly used center drill bit sizes.

Size designation	Drill diameter [inches (mm)]
5/0	0.010 in (0.254 mm)
4/0	0.015 in (0.381 mm)
3/0	0.020 in (0.508 mm)
two/0	0.025 in (0.635 mm)
0	1/32 in (0.794 mm)
1	three/64 in (one.191 mm)
ii	5/64 in (1.984 mm)
3	7/64 in (ii.778 mm)
iv	1/8 in (3.175 mm)
4½	nine/64 in (3.572 mm)
5	3/16 in (iv.763 mm)
6	7/32 in (5.556 mm)
7	1/4 in (vi.350 mm)
eight	5/16 in (vii.938 mm)
Gauge	Torso diameter [inches (mm)]
BS1	1/viii in (three.175 mm)
BS2	3/xvi in (four.763 mm)
BS3	ane/4 in (6.350 mm)
BS4	5/sixteen in (7.938 mm)
BS5	7/16 in (eleven.113 mm)
BS5A	1/2 in (12.700 mm)
BS6	v/8 in (15.875 mm)
BS7	3/iv in (19.050 mm)

Drill Fleck Lengths

The length of drill bits vary depending on their application.

Jobber-length drill bits are the most common, with a length somewhere between 9 to 14 times the diameter.
Screw-machine-length drills arethe shortest available standard sized bits. They are used primarily in machinist workshops for spiral machinesand are not usually available in hardware stores.
Shipping-length drills are extended length drill bits that are manufactured in fixed length such as iv, 6, 8, 12, 18, 24-inch $.25, rather than proportional lengths.