Drill bit Length Chart

Drill bit Length Chart

The table shows the sizes of straight shank drills.

In the United States, three different systems for designating twist drill sizes are used:

• letters (Morse gauge)
• fractional inches
• millimeters
• numbers, with higher numbers representing smaller drills.

The lengths in the table are “jobber’s lengths”. Very long twist drills, (“aircraft drills” or “electrician’s drill”) are available in 6, 12, and even 24-inch lengths.

Price: $159.95

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Size		Long Length		Regular Length		Short Length
Size	Flute Length	Flute Length	Overall Length	Overall Length	Dec.	Flute Length	Overall Length
1/64	5/16	3/16	3/4	1-1/2	0.0156
1/32	3/4	1/2	1-3/8	2	0.0312
3/64	1-1/8	3/4	1-3/4	2-1/4	0.0469	1/2	1-3/8
1/16	1-3/4	7/8	1-7/8	3	0.0625	5/8	1-5/8
5/64	2	1	2	3-3/4	0.0781	11/16	1-11/16
3/32	2-1/4	1-1/4	2-1/4	4-1/4	0.0937	3/4	1-3/4
7/64	2-1/2	1-1/2	2-5/8	4-5/8	0.1094	13/16	1-13/16
1/8	2-3/4	1-5/8	2-3/4	5-1/8	0.1250	7/8	1-7/8
9/64	3	1-3/4	2-7/8	5-3/8	0.1406	15/16	1-15/16
5/32	3	2	3-1/8	5-3/8	0.1562	1	2-1/16
11/64	3-3/8	2-1/8	3-1/4	5-3/4	0.1719	1-1/16	2-1/8
3/16	3-3/8	2-5/16	3-1/2	5-3/4	0.1875	1-1/8	2-3/16
13/64	3-5/8	2-7/16	3-5/8	6	0.2031	1-3/16	2-1/4
7/32	3-5/8	2-1/2	3-3/4	6	0.2188	1-1/4	2-3/8
15/64	3-3/4	2-5/8	3-7/8	6-1/8	0.2344	1-5/16	2-7/16
1/4	3-3/4	2-3/4	4	6-1/8	0.2500	1-3/8	2-1/2
17/64	3-7/8	2-7/8	4-1/8	6-1/4	0.2656	1-7/16	2-5/8
9/32	3-7/8	2-15/16	4-1/4	6-1/4	0.2812	1-1/2	2-11/16
19/64	4	3-1/16	4-3/8	6-3/8	0.2969	1-9/16	2-3/4
5/16	4	3-3/16	4-1/2	6-3/8	0.3125	1-5/8	2-13/16
21/64	4-1/8	3-5/16	4-5/8	6-1/2	0.3281	1-11/16	2-15/16
11/32	4-1/8	3-7/16	4-3/4	6-1/2	0.3438	1-11/16	3
23/64	4-1/4	3-1/2	4-7/8	6-3/4	0.3594	1-3/4	3-1/16
3/8	4-1/4	3-5/8	5	6-3/4	0.3750	1-13/16	3-1/8
25/64	4-3/8	3-3/4	5-1/8	7	0.3906	1-7/8	3-1/4
13/32	4-3/8	3-7/8	5-1/4	7	0.4062	1-15/16	3-5/16
27/64	4-5/8	3-15/16	5-3/8	7-1/4	0.4219	2	3-3/8
7/16	4-5/8	4-1/16	5-1/2	7-1/4	0.4375	2-1/16	3-7/16
29/64	4-3/4	4-3/16	5-5/8	7-1/2	0.4531	2-1/8	3-9/16
15/32	4-3/4	4-5/16	5-3/4	7-1/2	0.4688	2-1/8	3-5/8
31/64	4-3/4	4-3/8	5-7/8	7-3/4	0.4844	2-3/16	3-11/16
1/2	4-3/4	4-1/2	6	7-3/4	0.5000	2-1/4	3-3/4
33/64	4-3/4	4-13/16	6-5/8	8	0.5156	2-3/8	3-7/8
17/32	4-3/4	4-13/16	6-5/8	8	0.5312	2-3/8	3-7/8
35/64	4-7/8	4-1316	6-5/8	8-1/4	0.5469	2-1/2	4
9/16	4-7/8	4-13/16	6-5/8	8-1/4	0.5625	2-1/2	4
37/64	4-7/8	4-13/16	6-5/8	8-3/4	0.5781	2-5/8	4-1/8
19/32	4-7/8	5-3/16	7-1/8	8-3/4	0.5938	2-5/8	4-1/8
39/64	4-7/8	5-3/16	7-1/8	8-3/4	0.6094	2-3/4	4-1/4
5/8	4-7/8	5-3/16	7-1/8	8-3/4	0.6250	2-3/4	4-1/4
41/64	5-1/8	5-3/16	7-1/8	9	0.6406	2-7/8	4-1/2
21/32	5-1/8	5-3/16	7-1/8	9	0.6562	2-7/8	4-1/2
43/64	5-3/8	5-5/8	7-5/8	9-1/4	0.6719	2-7/8	4-5/8
11/16	5-3/8	5-5/8	7-5/8	9-1/4	0.6875	2-7/8	4-5/8
45/64	5-5/8			9-1/2	0.7031	3	4-3/4
23/32	5-5/8			9-1/2	0.7188	3	4-3/4
47/64	5-7/8			9-3/4	0.7344	3-1/8	5
3/4	5-7/8			9-3/4	0.7500	3-1/8	5
49/64	6			9-7/8	0.7656	3-1/4	5-1/8
25/32	6			9-7/8	0.7812	3-1/4	5-1/8
51/64	6-1/8			10	0.7969	3-3/8	5-1/4
13/16	6-1/8			10	0.8125	3-3/8	5-1/4
53/64	6-1/8			10	0.8281	3-1/2	5-3/8
27/32	6-1/8			10	0.8438	3-1/2	5-3/8
55/64	6-1/8			10	0.8594	3-1/2	5-1/2
7/8	6-1/8			10	0.8750	3-1/2	5-1/2
57/64	6-1/8			10	0.8906	3-5/8	5-5/8
29/32	6-1/8			10	0.9062	3-5/8	5-5/8
59/64	6-1/8			10-3/4	0.9219	3-3/4	5-3/4
15/16	6-1/8			10-3/4	0.9375	3-3/4	5-3/4
61/64	6-3/8			11	0.9531	3-7/8	5-7/8
31/32	6-3/8			11	0.9688	3-7/8	5-7/8
63/64	6-3/8			11	0.9844	4	6
1	6-3/8			11	10.000	4	6
1-1/8	7-1/8			11-3/4	10.125	4	6-3/8

Price: $7.29

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