Circuit Supply Solutions, Inc.

Drilling Processes 101

The purpose of through-hole drilling printed circuit boards is twofold: (1) to produce an opening through the board that will permit a subsequent process to form an electrical connection between top, bottom, and internal conductor pathways, and (2) to permit through-the-board component mounting with structural integrity and precision of location.

The quality of a hole drilled through a printed circuit board is measured by its ability to interface with the following processes: plating, soldering, and forming a highly reliable, non-degrading electrical and mechanical connection.

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Drill Size Chart - Click here for a Printable PDF

Size	Decimal Inch	Size	Decimal Inch	Size	Decimal Inch	Size	Decimal Inch
0.05 mm	0.0020	#59	0.0410	2.70 mm	0.1063	#16	0.1770
0.10 mm	0.0039	1.05 mm	0.0413	#36	0.1065	4.50 mm	0.1772
0.13 mm	0.0051	#58	0.0420	2.75 mm	0.1083	4.55 mm	0.1791
0.15 mm	0.0059	#57	0.0430	7/64	0.1094	#15	0.1800
#97	0.0059	1.10 mm	0.0433	#35	0.1100	4.60 mm	0.1811
#96	0.0063	1.15 mm	0.0453	2.80 mm	0.1102	#14	0.1820
#95	0.0067	#56	0.0465	#34	0.1110	4.65 mm	0.1831
#94	0.0071	3/64	0.0469	2.85 mm	0.1122	4.70 mm	0.1850
#93	0.0075	1.20 mm	0.0472	#33	0.1130	#13	0.1850
0.20 mm	0.0079	1.25 mm	0.0492	2.90 mm	0.1142	4.75 mm	0.1870
#92	0.0079	1.30 mm	0.0512	#32	0.1160	3/16	0.1875
#91	0.0083	#55	0.0520	2.95 mm	0.1161	4.80 mm	0.1890
#90	0.0087	1.35 mm	0.0531	3.00 mm	0.1181	#12	0.1890
#89	0.0091	#54	0.0550	#31	0.1200	4.85 mm	0.1909
#88	0.0095	1.40 mm	0.0551	3.05 mm	0.1201	#11	0.1910
0.25 mm	0.0098	1.45 mm	0.0571	3.10 mm	0.1220	4.90 mm	0.1929
#87	0.0100	1.50 mm	0.0591	3.15 mm	0.1240	#10	0.1935
#86	0.0105	#53	0.0595	1/8"	0.1250	4.95 mm	0.1949
#85	0.0110	1.55 mm	0.0610	3.20 mm	0.1260	#9	0.1960
#84	0.0115	1/16"	0.0625	3.25 mm	0.1280	5.00 mm	0.1969
0.30 mm	0.0118	1.60 mm	0.0630	#30	0.1285	5.05 mm	0.1988
#83	0.0120	#52	0.0635	3.30 mm	0.1299	#8	0.1990
#82	0.0125	1.65 mm	0.0650	3.35 mm	0.1319	5.10 mm	0.2008
#81	0.0130	1.70 mm	0.0669	3.40 mm	0.1339	#7	0.2010
#80	0.0135	#51	0.0670	3.45 mm	0.1358	5.15 mm	0.2028
0.35 mm	0.0138	1.75 mm	0.0689	#29	0.1360	#6	0.2040
#79	0.0145	#50	0.0700	3.50 mm	0.1378	5.20 mm	0.2047
0.40 mm	0.0157	1.80 mm	0.0709	3.55 mm	0.1398	#5	0.2055
#78	0.0160	1.85 mm	0.0728	#28	0.1405	5.25 mm	0.2067
0.45 mm	0.0177	#49	0.0730	3.60 mm	0.1417	5.30 mm	0.2087
#77	0.0180	1.90 mm	0.0748	3.65 mm	0.1437	#4	0.2090
0.50 mm	0.0197	#48	0.0760	#27	0.1440	5.35 mm	0.2106
#76	0.0200	1.95 mm	0.0768	3.70 mm	0.1457	5.40 mm	0.2126
#75	0.0210	5/64	0.0781	#26	0.1470	#3	0.2130
0.55 mm	0.0217	#47	0.0785	3.75 mm	0.1476	5.45 mm	0.2146
#74	0.0225	2.00 mm	0.0787	#25	0.1495	5.50 mm	0.2165
0.60 mm	0.0236	2.05 mm	0.0807	3.80 mm	0.1496	5.55 mm	0.2185
#73	0.0240	#46	0.0810	3.85 mm	0.1516	5.60 mm	0.2205
#72	0.0250	#45	0.0820	#24	0.1520	#2	0.2210
0.65 mm	0.0256	2.10 mm	0.0827	3.90 mm	0.1535	5.65 mm	0.2224
#71	0.0260	2.15 mm	0.0846	#23	0.1540	5.70 mm	0.2244
0.70 mm	0.0276	#44	0.0860	3.95 mm	0.1555	5.75 mm	0.2264
#70	0.0280	2.20 mm	0.0866	5/32	0.1563	#1	0.2280
#69	0.0292	2.25 mm	0.0886	#22	0.1570	5.80 mm	0.2283
0.75 mm	0.0295	#43	0.0890	4.00 mm	0.1575	5.85 mm	0.2303
#68	0.0310	2.30 mm	0.0906	#21	0.1590	5.90 mm	0.2323
1/32	0.0313	2.35 mm	0.0925	4.05 mm	0.1594	5.95 mm	0.2343
0.80 mm	0.0315	#42	0.0935	#20	0.1610	6.00 mm	0.2362
#67	0.0320	3/32	0.0938	4.10 mm	0.1614	6.05 mm	0.2382
#66	0.0330	2.40 mm	0.0945	4.15 mm	0.1634	6.10 mm	0.2402
0.85 mm	0.0335	#41	0.0960	4.20 mm	0.1654	6.15 mm	0.2421
#65	0.0350	2.45 mm	0.0965	#19	0.1660	6.20 mm	0.2441
0.90 mm	0.0354	#40	0.0980	4.25 mm	0.1673	6.25 mm	0.2461
#64	0.0360	2.50 mm	0.0984	4.30 mm	0.1693	6.30 mm	0.2480
#63	0.0370	#39	0.0995	#18	0.1695	6.35 mm	0.2500
0.95 mm	0.0374	2.55 mm	0.1004	4.35 mm	0.1713	1/4	0.2500
#62	0.0380	#38	0.1015	11/64	0.1719	6.40 mm	0.2520
#61	0.0390	2.60 mm	0.1024	#17	0.1730	6.45 mm	0.2539
1.00 mm	0.0394	#37	0.1040	4.40 mm	0.1732	6.50 mm	0.2559
#60	0.0400	2.65 mm	0.1043	4.45 mm	0.1752	Ltr. F	0.2570