*DRILL SIZES FOR Free Cutting Metals Steel, Aluminum Copper and Copper Alloys | |
---|---|
Drill Size | Decimal |
56 | .0465 |
53 | .0595 |
53 | .0595 |
51 | .0670 |
50 | .0700 |
48 | .0760 |
48 | .0760 |
44 | .0860 |
43 | .0890 |
39 | .0995 |
38 | .1015 |
36 | .1065 |
33 | .1130 |
29 | .1360 |
29 | .1360 |
26 | .1470 |
5/32 | .1562 |
11/64 | .1719 |
15 | .1800 |
8 | .1990 |
3 | .2130 |
F | .2570 |
I | .2720 |
5/16 | .3125 |
Q | .3320 |
W | .3860 |
27/64 | .4219 |
31/64 | .4844 |
1/2 | .5000 |
17/32 | .5312 |
9/16 | .5625 |
21/32 | .6562 |
11/16 | .6875 |
49/64 | .7656 |
51/64 | .7969 |
7/8 | .8750 |
59/64 | .9219 |
*Drill sizes recommended for “Free Cutting Materials” produces 65-75% of thread. **For “Hard or Rough Materials”, 60-70% of thread. |
|
TAPPING TIPS Strength of tapped holes: Strength tests show that any increase over 60% of thread for the tapped holes does not increase static strength of fastening. Bolts break at 55% of engagement. Tapping blind holes: Drill hole deep enough to accommodate chips. Tap breakage: If difficulty or breakage occurs, check drill size in view of material hardness and make sure tap is sharp. Breaking small drills: Small drills (1/8″ and under) break easily when they are not run at high speeds. Difficulty in drilling: If starting drill is difficult, thinning web of drill at the point solves this problem. Class of fit: Most commercial bolts and screws are made to fit 2A external thread standards, which fit with 2B tapped threads. |
Tap Size | ||
---|---|---|
Diameter | Threads Per Inch | |
UNC | UNF | |
0 | 80 | |
1 | 64 | |
72 | ||
2 | 56 | |
64 | ||
3 | 48 | |
46 | ||
4 | 40 | |
48 | ||
5 | 40 | |
44 | ||
6 | 32 | |
40 | ||
8 | 32 | |
36 | ||
10 | 24 | |
32 | ||
12 | 24 | |
28 | ||
1/4 | 20 | |
28 | ||
5/16 | 18 | |
24 | ||
3/8 | 16 | |
24 | ||
7/16 | 14 | |
20 | ||
1/2 | 13 | |
20 | ||
9/16 | 12 | |
18 | ||
5/8 | 11 | |
18 | ||
3/4 | 10 | |
16 | ||
7/8 | 9 | |
14 | ||
1 | 8 | |
12 | ||
*Drill sizes recommended for “Free Cutting Materials” produces 65-75% of thread. **For “Hard or Rough Materials”, 60-70% of thread. |
||
TAPPING TIPS Strength of tapped holes: Strength tests show that any increase over 60% of thread for the tapped holes does not increase static strength of fastening. Bolts break at 55% of engagement. Tapping blind holes: Drill hole deep enough to accommodate chips. Tap breakage: If difficulty or breakage occurs, check drill size in view of material hardness and make sure tap is sharp. Breaking small drills: Small drills (1/8″ and under) break easily when they are not run at high speeds. Difficulty in drilling: If starting drill is difficult, thinning web of drill at the point solves this problem. Class of fit: Most commercial bolts and screws are made to fit 2A external thread standards, which fit with 2B tapped threads. |
**DRILL SIZES FOR Hard or Tough Metals Carbon & Alloy Steel, Heat Treated Steels, Stnls Steels |
|
---|---|
Drill Size | Decimal |
3/64 | .0469 |
53 | .0595 |
53 | .0595 |
50 | .0700 |
49 | .0730 |
46 | .0810 |
45 | .0820 |
43 | .0890 |
42 | .0935 |
38 | .1015 |
37 | .1040 |
7/64 | .1094 |
32 | .1160 |
29 | .1360 |
28 | .1405 |
24 | .1520 |
21 | .1590 |
16 | .1770 |
14 | .1820 |
6 | .2040 |
7/32 | .2188 |
14/64 | .2656 |
J | .2770 |
P | .3230 |
R | .3390 |
3/8 | .3750 |
25/64 | .3906 |
7/16 | .4375 |
29/64 | .4531 |
1/2 | .5000 |
33/64 | .5156 |
35/64 | .5469 |
37/64 | .5781 |
43/64 | .6719 |
45/364 | .7031 |
25/32 | .7812 |
13/16 | .8125 |
57/64 | .8906 |
15/16 | .9375 |
*Drill sizes recommended for “Free Cutting Materials” produces 65-75% of thread. **For “Hard or Rough Materials”, 60-70% of thread. |
|
TAPPING TIPS Strength of tapped holes: Strength tests show that any increase over 60% of thread for the tapped holes does not increase static strength of fastening. Bolts break at 55% of engagement. Tapping blind holes: Drill hole deep enough to accommodate chips. Tap breakage: If difficulty or breakage occurs, check drill size in view of material hardness and make sure tap is sharp. Breaking small drills: Small drills (1/8″ and under) break easily when they are not run at high speeds. Difficulty in drilling: If starting drill is difficult, thinning web of drill at the point solves this problem. Class of fit: Most commercial bolts and screws are made to fit 2A external thread standards, which fit with 2B tapped threads. |