Contact Us

Ohio Drill & Tool Company
23255 Georgetown Rd.

P.O. Box 154 
Homeworth, OH 44634
(330) 525-7717

(800) 826-5237
Fax: (330) 525-5432
 

Taper Length Half Rounds

Half round drills have become widely used in the screw machine industry.  They are designed for quick  penetration in brass and other free maching metals.  These drills provide greater chip clearance, which is desirable in deep hole drilling where extra length is needed.  This tool will provide a very smooth finish in many applications.  Drills are not tapered.  118 deg. standard drill point.

 

Fractional Sizes
catalog page: 37
Size Part Number Decimal Equivalent Overall Length Flute Length
1/64 425001 .0156 1-3/4 3/8
1/32 425002 .0312 2-7/8 1-1/2
3/64 425003 .0469 2-1/4 1-1/8
1/16 425004 .0625 3 1-3/4
5/64 425005 .0781 3-3/4 2
3/32 425006 .0938 4-1/4 2-1/4
7/64 425007 .1094 4-5/8 2-1/2
1/8 425008 .1250 5-1/8 2-3/4
9/64 425009 .1406 5-3/8 3
5/32 425010 .1563 5-3/8 3
11/64 425011 .1719 5-3/4 3-3/8
3/16 425012 .1875 5-3/4 3-3/8
13/64 425013 .2031 6 3-5/8
7/32 425014 .2188 6 3-5/8
15/64 425015 .2344 6-1/8 3-3/4
1/4 425016 .2500 6-1/8 3-3/4
17/64 425017 .2656 6-1/4 3-7/8
9/32 425018 .2813 6-1/4 3-7/8
19/64 425019 .2969 6-3/8 4
5/16 425020 .3125 6-3/8 4
21/64 425021 .3281 6-1/2 4-1/8
11/32 425022 .3438 6-1/2 4-1/8
23/64 425023 .3594 6-3/4 4-1/4
3/8 425024 .3750 6-3/4 4-1/4
25/64 425025 .3906 7 4-3/8
13/32 425026 .4063 7 4-3/8
27/64 425027 .4219 7-1/4 4-5/8
7/16 425028 .4375 7-1/4 4-5/8
29/64 425029 .4531 7-1/2 4-3/4
15/32 425030 .4688 7-1/2 4-3/4
31/64 425031 .4844 7-3/4 4-3/4
1/2 425032 .5000 7-3/4 4-3/4
Letter Sizes
catalog page: 37
Size Part Number Decimal Equivalent Overall Length Flute Length
A 427901 .2340 6-1/8 3-3/4
B 427902 .2380 6-1/8 3-3/4
C 427903 .2420 6-1/8 3-3/4
D 427904 .2460 6-1/8 3-3/4
E 427905 .2500 6-1/8 3-3/4
F 427906 .2570 6-1/4 3-7/8
G 427907 .2610 6-1/4 3-7/8
H 427908 .2660 6-1/4 3-7/8
I 427909 .2720 6-1/4 3-7/8
J 427910 .2770 6-1/4 3-7/8
K 427911 .2810 6-1/4 3-7/8
L 427912 .2900 6-3/8 4
M 427913 .2950 6-3/8 4
N 427914 .3020 6-3/8 4
O 427915 .3160 6-1/2 4-1/8
P 427916 .3230 6-1/2 4-1/8
Q 427917 .3320 6-1/2 4-1/8
R 427918 .3390 6-1/2 4-1/8
S 427919 .3480 6-3/4 4-1/4
T 427920 .3580 6-3/4 4-1/4
U 427921 .3680 6-3/4 4-1/4
V 427922 .3770 7 4-3/8
W 427923 .3860 7 4-3/8
X 427924 .3970 7 4-3/8
Y 427925 .4040 7 4-3/8
Z 427926 .4130 7-1/4 4-5/8
Wire Gauge Sizes
catalog page: 38
Size Part Number Decimal Equivalent Overall Length Flute Length
1 426801 .2280 6-1/8 3-3/4
2 426802 .2210 6-1/8 3-3/4
3 426803 .2130 6 3-5/8
4 426804 .2090 6 3-5/8
5 426805 .2055 6 3-5/8
6 426806 .2040 6 3-5/8
7 426807 .2010 6 3-5/8
8 426808 .1990 6 3-5/8
9 426809 .1960 6 3-5/8
10 426810 .1935 6 3-5/8
11 426811 .1910 6 3-5/8
12 426812 .1890 6 3-5/8
13 426813 .1850 5-3/4 3-3/8
14 426814 .1820 5-3/4 3-3/8
15 426815 .1800 5-3/4 3-3/8
16 426816 .1770 5-3/4 3-3/8
17 426817 .1730 5-3/4 3-3/8
18 426818 .1695 5-3/4 3-3/8
19 426819 .1660 5-3/4 3-3/8
20 426820 .1610 5-3/4 3-3/8
21 426821 .1590 5-3/4 3-3/8
22 426822 .1570 5-3/4 3-3/8
23 426823 .1540 5-3/8 3
24 426824 .1520 5-3/8 3
25 426825 .1495 5-3/8 3
26 426826 .1470 5-3/8 3
27 426827 .1440 5-3/8 3
28 426828 .1405 5-3/8 3
29 426829 .1360 5-3/8 3
30 426830 .1285 5-3/8 3
31 426831 .1200 5-1/8 2-3/4
32 426832 .1160 5-1/8 2-3/4
33 426833 .1130 5-1/8 2-3/4
34 426834 .1110 5-1/8 2-3/4
35 426835 .1100 5-1/8 2-3/4
36 426836 .1065 4-5/8 2-1/2
37 426837 .1040 4-5/8 2-1/2
38 426838 .1015 4-5/8 2-1/2
39 426839 .0995 4-5/8 2-1/2
40 426840 .0980 4-5/8 2-1/2
41 426841 .0960 4-5/8 2-1/2
42 426842 .0935 4-1/4 2-1/4
43 426843 .0890 4-1/4 2-1/4
44 426844 .0860 4-1/4 2-1/4
45 426845 .0820 4-1/4 2-1/4
46 426846 .0810 4-1/4 2-1/4
47 426847 .0785 4-1/4 2-1/4
48 426848 .0760 3-3/4 2
49 426849 .0730 3-3/4 2
50 426850 .0700 3-3/4 2
51 426851 .0670 3-3/4 2
52 426852 .0635 3-3/4 2
53 426853 .0595 3 1-3/4
54 426854 .0550 3 1-3/4
55 426855 .0520 3 1-3/4
56 426856 .0465 2-1/4 1-1/8
57 426857 .0430 2-1/4 1-1/8
58 426858 .0420 2-1/4 1-1/8
59 426859 .0410 2-1/4 1-1/8
60 426860 .0400 2-1/4 1-1/8
61 426861 .0390 3 1-3/4
62 426862 .0380 3 1-3/4
63 426863 .0370 3 1-3/4
64 426864 .0360 3 1-3/4
65 426865 .0350 3 1-3/4
66 426866 .0330 3 1-5/8
67 426867 .0320 3 1-5/8
68 426868 .0310 2-7/8 1-1/4
69 426869 .0292 2-3/4 1
70 426870 .0280 2-5/8 3/4
71 426871 .0260 2-5/8 3/4
72 426872 .0250 2-1/2 5/8
73 426873 .0240 2-3/8 5/8
74 426874 .0225 2-1/4 1/2
75 426875 .0210 2-1/8 1/2
76 426876 .0200 2 3/8
77 426877 .0180 1-7/8 3/8
78 426878 .0160 1-3/4 3/8
79 426879 .0145 1-1/2 3/8
80 426880 .0135 1-1/2 3/8
 
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