Drill/Tap Chart - Coil Threaded Inserts for Metal

This specialized drill and tap chart is designed for E-Z LOK coil threaded inserts used in metal applications. These helical wire thread inserts provide superior thread strength and durability in metal materials including aluminum, steel, and other alloys. Find the correct drill size, STI tap specification, and installation tool for your coil insert installation. Available in standard wall configurations for both coarse and fine Unified (inch) threads, as well as coarse, fine, and spark plug Metric threads.

Important Note: Coil inserts require the use of an STI tap for proper thread preparation in metal applications.

Standard Wall - Inch - Coarse

Coil Inserts for Metal

Thread Size	Drill	Tap	Install Tool
2-56	3/32	2-56 STI	M1002
3-48	#36	3-48 STI	M1002
4-40	#31	4-40 STI	M1004
5-40	#29	5-40 STI	M1004
6-32	#25	6-32 STI	M1005
8-32	11/64	8-32 STI	M1006
10-24	13/64	10-24 STI	M1007
12-24	15/64	12-24 STI	M1008
1/4-20	17/64	1/4-20 STI	M1009
5/16-18	21/64	5/16-18 STI	M1010
3/8-16	25/64	3/8-16 STI	M1012
7/16-14	29/64	7/16-14 STI	M1014
1/2-13	33/64	1/2-13 STI	M1015
9/16-12	37/64	9/16-12 STI	M1015
5/8-11	21/32	5/8-11 STI	M1018
3/4-10	25/32	3/4-10 STI	M1020
7/8-9	29/32	7/8-9 STI	M1022
1-8	1-1/32	1-8 STI	M1023
1-1/8-7	1-5/32	1-1/8-7 STI	M1024
1-1/4-7	1-9/32	1-1/4-7 STI	M1025
1-3/8-6	1-13/32	1-3/8-6 STI	M1026
1-1/2-6	1-17/32	1-1/2-6 STI	M1027

Standard Wall - Inch - Fine

Coil Inserts for Metal

Thread Size	Drill	Tap	Install Tool
4-48	#31	4-48 STI	M1004
6-40	#25	6-40 STI	M1005
8-36	11/64	8-36 STI	M1006
10-32	13/64	10-32 STI	M1008
1/4-28	17/64	1/4-28 STI	M1009
5/16-24	21/64	5/16-24 STI	M1011
3/8-24	25/64	3/8-24 STI	M1013
7/16-20	29/64	7/16-20 STI	M1014
1/2-20	33/64	1/2-20 STI	M1015
9/16-18	37/64	9/16-18 STI	M1017
5/8-18	41/64	5/8-18 STI	M1018
3/4-16	49/64	3/4-16 STI	M1021
7/8-14	57/64	7/8-14 STI	M1022
1-12	1-1/64	1-12 STI	M1023
1-14	1-1/64	1-14 STI	M1023
1-1/8-12	1-5/32	1-1/8-12 STI	M1028
1-1/4-12	1-9/32	1-1/4-12 STI	M1029
1-3/8-12	1-13/32	1-3/8-12 STI	M1030
1-1/2-12	1-17/32	1-1/2-12 STI	M1031

Standard Wall - Metric - Coarse

Coil Inserts for Metal

Thread Size	Drill	Tap	Install Tool
M2-0.4	2.1	M2-0.4 STI	M1002
M2.5-0.45	2.6	M2.5-0.45 STI	M1002
M3-0.5	3.1	M3-0.5 STI	M1004
M3.5-0.6	3.6	M3.5-0.6 STI	M1005
M4-0.7	4.1	M4-0.7 STI	M1006
M5-0.8	5.2	M5-0.8 STI	M1008
M6-1.0	6.2	M6-1.0 STI	M1009
M7-1.0	7.2	M7-1.0 STI	M1010
M8-1.25	8.3	M8-1.25 STI	M1011
M10-1.5	10.3	M10-1.5 STI	M1013
M11-1.5	11.3	M11-1.5 STI	M1014
M12-1.75	12.4	M12-1.75 STI	M1015
M14-2.0	14.5	M14-2.0 STI	M1015
M16-2.0	16.5	M16-2.0 STI	M1018
M18-2.5	18.5	M18-2.5 STI	M1020
M20-2.5	20.5	M20-2.5 STI	M1021
M22-2.5	22.5	M22-2.5 STI	M1022
M24-3.0	24.75	M24-3.0 STI	M1023
M27-3.0	27.5	M27-3.0 STI	M1032
M30-3.5	30.5	M30-3.5 STI	M1033
M33-3.5	33.5	M33-3.5 STI	M1034
M36-4.0	36.5	M36-4.0 STI	M1035
M39-4.0	39.5	M39-4.0 STI	M1036

Standard Wall - Metric - Fine

Coil Inserts for Metal

Thread Size	Drill	Tap	Install Tool
M8-1.0	8.3	M8-1.0 STI	M1011
M10-1.25	10.3	M10-1.25 STI	M1013
M12-1.5	12.4	M12-1.5 STI	M1015
M14-1.5	14.3	M14-1.5 STI	M1016
M16-1.5	16.25	M16-1.5 STI	M1018
M18-2.0	18.5	M18-2.0 STI	M1020
M20-2.0	20.5	M20-2.0 STI	M1020
M22-2.0	22.5	M22-2.0 STI	M1022
M24-2.0	24.25	M24-2.0 STI	M1023

Standard Wall - Metric - Spark Plug

Coil Inserts for Metal

Thread Size	Drill	Tap	Install Tool
M10-1.0	10.3	M10-1.0 STI	M1014
M12-1.25	12.4	M12-1.25 STI	M1015
M14-1.25	14.3	M14-1.25 STI	M1017
M18-1.5	18.25	M18-1.5 STI	M1020