OSCILLATING ENGINES. 233
—for the best means of fitting—and lugs atthe top and bottom sides render them sta-tionary. The dotted curved portion underthe bearing in the entablature is the “ corehole,” that is stopped by a separate plate.
Fig. 63.
SHAFT BEARING IN ENTABLATURE.
Fore and aft of the bearings the entablatureis usually solid, as a parallelogram in section,but a section as the letter inverted is some-tunes preferred.
To economise patterns and retain portabilityfitting and erection, the entablature isconnected centrally—longitudinally of the hull"—-by flanges, bolts, and nuts,'arid thus a bettercasting can be also ensured rather than if thewhole portion was entire.
To retain the rigidity of the detail in ques-tion, cross frames are often used indepen-
dently of the columns. The addition, however,may be said to be a matter of idea, ratheressentially, inasmuch that, if the columns areof sufficient strength and correctly situated,the cross frames will not be requisite as ameans of support.
The lateral adjustment of the entablatureis often effected by wedges, each having ascrewed end and nut to ensure the most minutemovement if required; and it is almost need-less to add that these wedges are fore and aft,and generally opposite each bearing.
The example illustrated being of importancein connection with other details, the followingdimensions are in common with those givenin page 230, referring to the disconnection of
the cranks :—
Ft.
In.
Diameter of Main Bearing
1
0i
Length
1
Thickness of Brasses ....
0
1£
Thickness of Cap .....
0
6
"Width of Cap .....
1
3
Thickness of Metal under Brass,
0
oi
■“'8
Thickness of Metal of Slides of Frame
0
3
Depth of ditto .....
1
4
Depth under Main Bearing from Centre
2
21
Diameter of Cap Bolts ....
0
4£
Distance between Centres of ditto
1
9£
Diameter of Columns ....
0
4i
Distance between Centres of Columns
3
10
Half length of Entablature from Centre of
Cylinder .....
5
3
Some makers have introduced wroughtiron entablatures for the double purpose of re-ducing the weight and increasing the strength.Messrs. James Watt and Co. have usedwrought iron in many instances for thesedetails, the form of which is shown by Fig. 4 6—page 206—also a cast iron example in page224—Fig. 54. It will be noticed that thebase of the entablature forms a straight linein one instance, rather than a curve as shown
2 L