— 78 — 
Manufacturing Limit- 
ations.* 
Workmansliip. 0 
Painting.* 
Thö amount of field rivetting must be reduced to a minimum. 
In puucliing plate or other iron, the diameter of the die shall in 
no case exceed the diameter of the punch by more than -h of an 
inch, and all holes must be clean cuts without torn or ragged edges. 
All rivet-holes must be 00 accurately spaced and puucbed that 
when the several parts forming one member are assembled together, 
a rivet rV mcli less iu diameter than the hole can be entered, hot, 
into any hole, without reaming or straining the iron by “ drifts.” 
The rivets when driven must completely fill the holes. 
The rivet-heads must be hemispherical and of a uniform size 
for the same sized rivets throughout the work. They must be full 
and neatly made, and bo concentric to the riyet-liole, and thoroughly 
pinch tlie connected pieces together. 
Wherever possible, all rivets must be macliino driven. 
Tlie several pieces forming one built member must fit closely 
together, aiul when riveted shall be free from twists, bends, or open 
joints. 
All joints in riveted work, whether iu tension or compression 
members, must be fully spliced, as no reliance will be placed upon 
abutting joint’s. The abutting ends, however, must be dressed 
straight and true so that there shall bo no open joints. 
All workmanship shall be first-class in every particular. 
Abutting joints in truss bridges shall be in exact contact 
throughout. . 
Bars which ai’e to be placed side by side in the structure, shall 
be bored at tlie same temperature and of such equal length that upon 
being piled on each other tlie pins shall pass through the holes at 
botli ends without driving. 
Whenever necessary for the protection of the thread, provision 
shall be made for the use of pilot nuts in erection. 
All iron work before leaving tlie shop shall be tlioronghly clean - 
ed from all loose scale and rust, and be given one good coating of 
P urc boiled linseed oil, well worked into all joints and open spaces. 
I11 riveted work the surfaces coming in contact shall each be 
painted before being riveted together. Bottoms of bed-plates, bear- 
ing-plates, and any parts which are not accessible for painting after 
erection shall liave two coats of paint ; the paint shall be a good 
quality of irou ore paint subject to approval of Chief Engineer. 
After the structure is erected, the iron work shall be thoroughly 
nud evenly painted with two additional coats of paiut, mixed witli 
pure linseed oil, of such color as may be directed, the tension 
members being, liowever, generally of lighter color than the 
compression members. 
* From the specifications of Theodore Cooper Esq., C.E, 
