408 Molesworth’s pocket-book
Strength of Shafting to Resist Lateral
Steess. .
D = Diameter in inches, or side, if square.
L = Length of shaft supported at both ends in
feet.
W — Weight applied on the centre iu lbs.
or D = V ——, where w = weight distributed in
2/i [lbs.
Round Shafts. Square Shafts.
For wood .. .. k — 40 .. .. 70
„ cast iron .. k =. 500 .. .. 850
„ wrought iion fe = 700 . > .. 1200
Table of Shafting.—Necks (ok Journals)
and Couplings.
Diameter of Neck. Length of Neck. Diameter of Length of Length of Box. Diameter of Box.
Coupling. Lap.
inches. inches. inches. inches. inches. inches.
2 4 3i 2i 5|
2 J- 5 4 3 6i 6f
3 6 4f 3é U n
3| Ci 31 8 9
4 1 6 4 8i 9*
5 8 u 5 9| Ui
6 9 9 6 12 13;
7 10i 10i Ti 14 16
8 12 , 12 8 16i 18
9 13J 13 9 18 20
10 Ui 14 10 l«i 22
11 15 16 11 20 24
12 16 17i 12 21 26
By the practice of some makers the length of neck=li diam.
The ueck or journal in high speed machines should be larger
than given in the table; pivoted bearings are made from 3 to
4 diameters long.