U. S. DEPARTMENT OF AGEICULTUEE. 
ed^^and \S^e^d . Subpunched and reamed holes shall be punched -f^ 
boles". mch smaller than the nominal diameter of tlie rivet and 
shall then be reamed to a diameter y^ inch larger than the 
nominal diameter of the rivet. The pmicli and die shall 
have the same relative sizes as specified for full-size 
punched holes. BmTs produced by reaming shall be re- 
moved T\dth a tool producing a yg-inch fillet around the 
edge of the hole. 
Eeaming of rivet holes shall be done with twist driUs or 
with short taper reamers. Reamers preferably shall not 
be directed by hand. No oU or gi'ease shall be used as a 
lubricant. 
n. Accuracy of Reamed or drilled holes shall be cylindrical and per- 
ed^hoies^^ ^ ' pcndicular to the member and their accuracy shall be the 
same as specified for punched holes except that, after 
reaming or drilling, 85 of SiHj group of 100 contiguous 
holes in the same surface, or in like proportion for any 
gi'oup of holes, shall not show an offset greater than -^ 
inch between adjacent thicknesses of metal. 
holi."^"^*^^^ °^ The drifting done during assembling shall be only such 
as to bring the parts into position, and not sufficient to 
enlarge the holes or distort the metal. 
reaming^ ^ ^ '^ ^ ^ General reaming jnfij be required, in which case a 
definite provision to this effect shall be included else- 
where in the contract. 
When general reaming is requu'ed, all rivet holes in 
main members shall be subpimched and reamed or drilled 
from the sohd. This requirement shall not apply to rivet 
holes in top and bottom chord lateral members, lateral 
hangers, truss and girder sway bracings, and to the lateral 
plates, connection angles, etc., connecting these members 
to the main members of the structure. Connection plates 
or other parts acting both as main member material 
and secondary (lateral, sway bracing, etc.) member 
material shall generally have subpunched and reamed 
holes in locations engaging similar holes in main members. 
Reaming shall be done after the pieces forming' a built 
member are assembled and firmly bolted together. No 
interchange of reamed parts will be permitted. 
14 Field con- ^-lien general reaming is required, or in punched work 
when specifically requu-ed by the engineer, holes for field 
connections, except those in lateral, longitudinal, and sway 
bracing, shall be reamed or drilled. Riveted trusses shall 
be assembled in the shop, the parts adjusted to line and 
fit, and the holes for field connections reamed or drilled 
while so assembled. Holes for other field connections 
shall be reamed or drilled \\'ith the connecting parts as- 
sembled, or else reamed or drilled to a metal templet 
not less than 1 inch thick. 
sembHn^^ ^" ^^^ surfaccs of metal to be in contact when assembled 
sem iDg. Q\y^^\[ be carefully painted with one coat of the paint 
specified for the shop coat. The paint shall be applied 
upon sm-faces free from dirt, loose mill scale or other 
