Threads 
per Inch. 
No. 
20 
18 
16 
H 
13 
12 
II 
10 
9 
8 
7 
5 士 
5 
5 
4 备 
4 备 
4 
4 
3i 
Si 
3 
Dia. at Boot 
of Thread. 
Inches. 
.185 
.•240 
•294 
•344 
490 
•454 
•507 
•620 
•731 
•837 
.940 
1.065 
1.160 
1.284 
1.389 
1.490 
1.615 
1.712 
1.962 
2.175 
2.425 
2.629 
2.879 
3.100 
3.317 
3.567 
3.798 
4.028 
4.255 
4.480 
4.750 
5.053 
5.203 
5 ギ 3 
SCREW THREADS. 
Angle of Thread 60°. Flat at Top and 
Uottom= I of pitch 
Nut* and Bolt Heads 
are determined by the following rules, 
which apply to Square and Hexagon 
Nuts both : 
Short diameter of rough nut 
=l^xdia. of bolt +Jin. 
Short diameter of finished nut 
=l jxdia. of bolt+1-10 in. 
Thickness of rough nut. 
= diameter of bolt. 
Thickness of finished nut 
= diameter of bolt — 1-16 iu. 
Short diameter of rough head 
=]^xdia. of bolt+i in. 
Short dia. of finished head 
=1 辜 X dia. of bolt+1-16 in. 
Thickness of rough head 
short dia. of head. 
Thickness of finished head 
=dia. of bolt — 1-16 in. 
The long diameter of a hexagon nut 
may be obtained by multiplying the 
short diameter by 1.15 5, and the long 
diameter of a square nut by multiply- 
ing the short diameter by 1.414. 
The above standards for screw threads, 
nuts and bolt heads, were recom- 
mended by the Franklin Institute in 
Dec. 18G4, The standard for screw 
threads has been very generally adopt- 
ed in the United States, but propor- 
tions recommended for nuts and bolt 
heads have not found general accept- 
ance because of the odd sizes of bar 一 
not usually rolled by the mills — requir- 
ed to make the nut. 
WEOUGHT SPIKES. 
Number to a keo ： of ISO lbs. 
Length. 
^ in. 
No. 
Ä in. 
No. 
t in. 
No. 
■Length. 
In. 
+ in. 
No, 
A in. 
No. 
i in. 
No. 
み in. 
No. 
i in. 
No. 
3 
3 1-2 
4 
4 r-2 
5 
6 
22$0 
1890 
1650 
I464 
1380 
I292 
1208 
H35 
1064 
950 
868 
742 
570 
7 
8 
9 
TO 
11 
12 
1161 
662 
655 
573 
482 
455 
424 
391 
445 
384 
300 
270 
249 
256 
306 
256 
240 
222 
203 
1 80 
— 193 — 
STANDARD SCREW THEEADS, NUTS 
AND BOLT HEADS. 
Recommended by the Franklin Institute. 
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- 0* 2 2 2 2 222 
of w. es 
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Di sc IU 
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