435
OF ENGINEERING JFOEMULÆ.
Shkinkage of Castings.
In locomotive cylinders .. ..
In pipes ... ...
Girders, beams, &c. ._________
Engine-beams, connecting rods
In large cylinders, .Bay 7 O-inch
diameter, 10-feet stroke, the
contraction of diameter.. ..
Ditto .. ..
Ditto, In length
In thin brass
In thick brass
In zinc .. ..
In lead .. ..
In copper ..
Bismuth .,
Tin.________
— A inch in a foot.
= i „
= i in 15 inches.
* 4 in 16 •>,
== § at top.
= i at 'bottom.
— i iu 16 inches.
ss i-in 9 „
= i in 10 „
== in a foot.
Rule for Change Wheels in Screw-cutting Lathes.
N = Njo. of threads per inch to be cut.
P = No. of threads per inch on traverse screw.
S = No. of teeth in wheel on mandrel.
W =c No. of teeth in stud wheel (gearing in S).
Y = No. of teeth in stud pinion (gearing in T).
T — No. of teeth in wheel on traverse screw.
N = p_T. W = N —•
SY PT
Weight of Leather Belting, Lbs. pek Foot. Run.
Breadth, ins. if 2 2* 3 3| 4 5 5 J-
Single, lbs,.. •20 •23 •29 •35 •40 •46 •52 •58 •63
Double, „ .. •40 •46 .’58 •69 •81 •92 l'"' 1-15 1-27
Breadth, ins. 6 Si 8 9 10 11 W
Single, lbs... •69 •75 •81 •86 •92 1-04 1’15 1-27 1-38
Double, „ ., 1-38 1-50 1’61 1-72 1-84 2-07 2-30 2'53 2-76
2 F 2