Screw Machine (Stub) Drill Bit Chart

Screw Machine Drill Bits (also know as stub or stubby drills) are shorter than standard length Jobber Length Drill Bits. The shorter rugged construction performs well in a broad range of materials.

They come in a wide range of sizes, finishes and materials such as High Speed Steel, Cobalt and Solid Carbide.

Screw machine drills are popular in the automotive and construction industries. They are often used in screw machine setup where spindle clearance is limited.

Screw machine drill bits' flute length and overall length are dependant on the diamater of the drill bit. See the chart below for these specifications.

Fractional Sizes Decimal Equivalent (Inches) Flute Length (Inches) Overall Length (Inches)
3/64” 0.0469 1/2” 1-3/8”
1/16” 0.0625 5/8” 1-5/8”
5/64” 0.0781 11/16” 1-11/16”
3/32” 0.0938 3/4” 1-3/4”
7/64” 0.1094 13/16” 1-13/16”
1/8” 0.125 7/8” 1-7/8”
9/64” 0.1406 15/16” 1-15/16”
5/32” 0.1562 1” 2-1/16”
11/64” 0.1719 1-1/16” 2-1/8”
3/16” 0.1875 1-1/8” 2-3/16”
13/64” 0.2031 1-3/16” 2-1/4”
7/32” 0.2188 1-1/4” 2-3/8”
15/64” 0.2344 1-5/16” 2-7/16”
1/4” 0.25 1-3/8” 2-1/2”
17/64” 0.2656 1-7/16” 2-5/8”
9/32” 0.2813 1-1/2” 2-11/16”
19/64” 0.2969 1-9/16” 2-3/4”
5/16” 0.3125 1-5/8” 2-13/16”
21/64” 0.3281 1-11/16” 2-15/16”
11/32” 0.3438 1-11/16” 3”
23/64” 0.3594 1-3/4” 3-1/16”
3/8” 0.375 1-13/16” 3-1/8”
25/64” 0.3906 1-7/8” 3-1/4”
13/32” 0.4062 1-15/16” 3-5/16”
27/64” 0.4219 2” 3-3/8”
7/16” 0.4375 2-1/16” 3-7/16”
29/64” 0.4531 2-1/8” 3-9/16”
15/32” 0.4688 2-1/8” 3-5/8”
31/64” 0.4844 2-3/16” 3-11/16”
1/2” 0.5 2-1/4” 3-3/4”
33/64” 0.5156 2-3/8” 3-7/8”
17/32” 0.5312 2-3/8” 3-7/8”
35/64” 0.5469 2-1/2” 4”
9/16” 0.5625 2-1/2” 4”
37/64” 0.5781 2-5/8” 4-1/8”
19/32” 0.5938 2-5/8” 4-1/8”
39/64” 0.6094 2-3/4” 4-1/4”
5/8” 0.625 2-3/4” 4-1/4”
41/64” 0.6406 2-7/8” 4-1/2”
21/32” 0.6562 2-7/8” 4-1/2”
43/64” 0.6719 2-7/8” 4-5/8”
11/16” 0.6875 2-7/8” 4-5/8”
45/64” 0.7031 3” 4-3/4”
23/32” 0.7188 3” 4-3/4”
47/64” 0.7344 3-1/8” 5”
3/4” 0.75 3-1/8” 5”
49/64” 0.7656 3-1/4” 5-1/8”
25/32” 0.7812 3-1/4” 5-1/8”
51/64” 0.7969 3-3/8” 5-1/4”
13/16” 0.8125 3-3/8” 5-1/4”
53/64” 0.8281 3-1/2” 5-3/8”
27/32” 0.8438 3-1/2” 5-3/8”
55/64” 0.8594 3-1/2” 5-1/2”
7/8” 0.875 3-1/2” 5-1/2”
57/64” 0.8906 3-5/8” 5-5/8”
29/32” 0.9062 3-5/8” 5-5/8”
59/64” 0.9219 3-3/4” 5-3/4”
15/16” 0.9375 3-3/4” 5-3/4”
61/64” 0.9531 3-7/8” 5-7/8”
31/32” 0.9688 3-7/8” 5-7/8”
63/64” 0.9844 4” 6”
1” 1 4” 6”
1-1/64” 1.0156 4” 6”
1-1/32” 1.0312 4” 6-1/4”
1-3/64” 1.0469 4” 6-1/4”
1-1/16” 1.0625 4” 6-1/4”
1-5/64” 1.0781 4” 6-1/4”
1-3/32” 1.0938 4” 6-1/4”
1-7/64” 1.1094 4” 6-1/4”
1-1/8” 1.125 4” 6-3/8”
1-9/64” 1.1406 4” 6-3/8”
1-5/32” 1.1562 4-1/4” 6-5/8”
1-11/64” 1.1719 4-1/4” 6-5/8”
1-3/16” 1.1875 4-1/4” 6-5/8”
1-1/4” 1.25 4-3/8” 6-3/4”
1-9/32” 1.2813 4-3/8” 7”
1-5/16” 1.3125 4-3/8” 7”
1-3/8” 1.375 4-1/2” 7-1/8”
1-13/32” 1.4062 4-3/4” 7-3/8”
1-7/16” 1.4375 4-3/4” 7-3/8”
1-1/2” 1.5 4-7/8” 7-1/2”
2” 2 5-5/8” 8-1/2”
       
Wire Sizes Decimal Equivalent (Inches) Flute Length (Inches) Overall Length (Inches)
1 0.228 1-5/16” 2-7/16”
2 0.221 1-5/16” 2-7/16”
3 0.213 1-1/4” 2-3/8”
4 0.209 1-1/4” 2-3/8”
5 0.2055 1-1/4” 2-3/8”
6 0.204 1-1/4” 2-3/8”
7 0.201 1-3/16” 2-1/4”
8 0.199 1-3/16” 2-1/4”
9 0.196 1-3/16” 2-1/4”
10 0.1935 1-3/16” 2-1/4”
11 0.191 1-3/16” 2-1/4”
12 0.189 1-3/16” 2-1/4”
13 0.185 1-1/8” 2-3/16”
14 0.182 1-1/8” 2-3/16”
15 0.18 1-1/8” 2-3/16”
16 0.177 1-1/8” 2-3/16”
17 0.173 1-1/8” 2-3/16”
18 0.1695 1-1/16” 2-1/8”
19 0.166 1-1/16” 2-1/8”
20 0.161 1-1/16” 2-1/8”
21 0.159 1-1/16” 2-1/8”
22 0.157 1-1/16” 2-1/8”
23 0.154 1” 2-1/16”
24 0.152 1” 2-1/16”
25 0.1495 1” 2-1/16”
26 0.147 1” 2-1/16”
27 0.144 1” 2-1/16”
28 0.1405 15/16” 1-15/16”
29 0.136 15/16” 1-15/16”
30 0.1285 15/16” 1-15/16”
31 0.12 7/8” 1-7/8”
32 0.116 7/8” 1-7/8”
33 0.113 7/8” 1-7/8”
34 0.111 7/8” 1-7/8”
35 0.11 7/8” 1-7/8”
36 0.1065 13/16” 1-13/16”
37 0.104 13/16” 1-13/16”
38 0.1015 13/16” 1-13/16”
39 0.0995 13/16” 1-13/16”
40 0.098 13/16” 1-13/16”
41 0.096 13/16” 1-13/16”
42 0.0935 3/4” 1-3/4”
43 0.089 3/4” 1-3/4”
44 0.086 3/4” 1-3/4”
45 0.082 3/4” 1-3/4”
46 0.081 3/4” 1-3/4”
47 0.0785 11/16” 1-11/16”
48 0.076 11/16” 1-11/16”
49 0.073 11/16” 1-11/16”
50 0.07 11/16” 1-11/16”
51 0.067 11/16” 1-11/16”
52 0.0635 11/16” 1-11/16”
53 0.0595 5/8” 1-5/8”
54 0.055 5/8” 1-5/8”
55 0.052 5/8” 1-5/8”
56 0.0465 1/2” 1-3/8”
57 0.043 1/2” 1-3/8”
58 0.042 1/2” 1-3/8”
59 0.041 1/2” 1-3/8”
60 0.04 1/2” 1-3/8”
       
Letter Sizes Decimal Equivalent (Inches) Flute Length (Inches) Overall Length (Inches)
A 0.234 1-5/16” 2-7/16”
B 0.238 1-3/8” 2-1/2”
C 0.242 1-3/8” 2-1/2”
D 0.246 1-3/8” 2-1/2”
E 0.25 1-3/8” 2-1/2”
F 0.257 1-7/16” 2-5/8”
G 0.261 1-7/16” 2-5/8”
H 0.266 1-1/2” 2-11/16”
I 0.272 1-1/2” 2-11/16”
J 0.277 1-1/2” 2-11/16”
K 0.281 1-1/2” 2-11/16”
L 0.29 1-9/16” 2-3/4”
M 0.295 1-9/16” 2-3/4”
N 0.302 1-5/8” 2-13/16”
O 0.316 1-11/16” 2-15/16”
P 0.323 1-11/16” 2-15/16”
Q 0.332 1-11/16” 3”
R 0.339 1-11/16” 3”
S 0.348 1-3/4” 3-1/16”
T 0.358 1-3/4” 3-1/16”
U 0.368 1-13/16” 3-1/8”
V 0.377 1-7/8” 3-1/4”
W 0.386 1-7/8” 3-1/4”
X 0.397 1-15/16” 3-5/16”
Y 0.404 1-15/16” 3-5/16”
Z 0.413 2” 3-3/8”