CHAPTER XXI. 
ORDER BILLS AND SHIPPING-BILLS. 
8e ndi 611 也 616 is necessity for liaste in building a bridge, time can be saved by 
^ P ar ti a I or dei. bill to the manufacturers before starting to make the work- 
yawings, or after they are partially pencilled, 
t 1 Preliminary order bills should include only those portions which are 
treatise “ Main Members，” and those details of the sizes of wliicli the 
an 1 J ls Cer tain ； for instance, stay plates, pins, brackets, and tlie plates and 
ö 邮 tor built beams. 
great 心 J en gth of the main members in the bill should be three-quarters of an inch 
eu ^ fi auT 11 ''出 flc ^ ua ^^ required, in order to allow for the dressing of rough 
^ eil{y th of C ' S l i0 . U ld there be any doubt in the designer’s mind concerning the exact 
vaJ ； .. an y P lec e, he should make the ordered length great enough to cover any 
= ； ^ 爾 eh there may be in the design. 
tl 1A course ， where there are bevelled euds on a piece, the extreme lensrtli plus 
^owance for waste must be given. 
allow . 10 a mim ber of small pieces are to be cut from one largo piece, an extra 
to a ° eil gth must be made to provide for the waste in cutting, say from au eighth 
^S*dra r,er °^ au for each short lengtli. After finishing tlie pencilling for a work- 
8 houlcl( わ ' U ;?’ • — rem aincler of the preliminary order bill maybe made out and sent. It 
ivic eel into the following groups, containing tlie measurements indicated : — 
Channels 
No. 
Depth 
Weight per foot 
Length 
Fimsned length 
Angles 
No. 
Thickness 
Legs Weight per foot Length 
Finished length 
I-beams 
No. 
Depth 
Weight per foot 
Length 
Finished length 
Plates 
No. 
Thickness 
Width 
•Length 
Finished length 
