MATERIALS AND WORKMANSHIP 51 



212. Sub-punching and Reaming. All material more than 

 j- in. thick shall be sub-punched and reamed or drilled from the 

 solid. 



When reaming is required the punch used shall have a diameter 

 not less than J in. smaller than the nominal diameter of the rivet. 

 Holes shall then be reamed to a diameter not more than ^ in. 

 larger than the nominal diameter of the rivet. All reaming shall 

 be done with twist drills and without using any lubricant. 

 (Pars. 208, 213.) 



213. Burrs. The outside burrs on reamed holes shall be 

 removed to the extent of making a fg-in. fillet. 



214. Reaming after Assembling.* When general reaming i& 

 required it shall be done after the pieces forming one built mem- 

 ber are assembled and firmly bolted together. If necessary to take 

 the pieces apart for shipping and handling the respective pieces 

 reamed together shall be so marked that they may be reassembled 

 in the same position in the final setting up. No interchange of 

 reamed parts will be allowed. 



215. Size of Rivets. The size of rivets, called for on the 

 plans, shall be understood to mean the actual size of the cold 

 rivet before heating. 



216. Rivets. Rivets shall be uniformly heated to a light 

 cherry red heat in a gas or oil furnace so constructed that it 

 can be adjusted to the proper temperature. 



They shall be driven by pressure tools wherever possible. 

 Pneumatic hammers shall be used in preference to hand driving 



217. Field Rivets. Field rivets shall be furnished to the 

 amount of 15 per cent plus ten rivets in excess of the nominal 

 number required for each size. 



218. Turned Bolts. Wherever bolts are used in place of 

 rivets which transmit shears the holes shall be reamed parallel 

 and the bolts turned to a driving fit. A washer not less than J 

 in. thick shall be used under the nut. 



219. Riveting. Rivets shall look neat and finished with 

 heads of approved shape, full and of equal size. They shall be 

 central on shank and grip the assembled pieces firmly. Recup- 

 ping and caulking will not be allowed. Loose, burned, or other- 



*This paragraph contains a special requirement which, to be valid under 

 these specifications, shall be specifically mentioned in the contract between 

 the purchaser and the manufacturer. 



