DERRICKS 



MAKING FAST A DERRICK GUY 



TWO boom derricks were used for setting the 

 steel, one of 40 tons' capacity, which was a 

 special construction designed with a 75-foot 

 mast and 65-foot boom. The mast and boom were 

 made of round timber with cast steel and forged 

 steel fittings. The mast was guyed with eight 1J- 

 iiich steel guy ropes; it weighed about 10 tons and 

 was equipped with f-ineh diameter wire rope tackles 

 for the topping and hoisting lifts, which were rove 

 with from 9 to 3 parts, diminishing as the work ad- 

 vanced and the loads decreased. It required about 

 three hours to raise this derrick up two floors as tin- 

 work progre-.-.ed. 



The hoisting tackle for the 25-ton derrick was 

 rove with f-inch steel wire rope about 2,500 feet long 

 and the lower block had a cast iron counterweight 

 weighing about 1,500 pounds to assist in overhauling. 

 It required about two hours to raise this derrick up 

 two floors as the work progressed. 



Chain slings were used for handling all material. 



| -'H 



SYSTEM OF 

 OPERATION 



It was necessary to erect a temporary platform of 

 steel and wood on the 14th tier at the front of the 

 building. On this platform the 40-ton derrick was 

 set and was operated with a hoisting engine perma- 

 nently set on the ground floor. The 

 25-ton derrick was used for setting 

 the steel work for the Tower; this 

 derrick was operated with an engine set on the l?lh 

 floor which was provided with steam from the boiler 

 that supplied the air compressors. 



The material was hoisted from the trucks by the 

 40-ton derrick, landed on the platform, then hoisted 

 l>\ I he 25-ton derrick and set in place on the Tower. 

 After setting two tiers of columns and beams tin- 

 derricks were raised to the top floor and the operation 

 was repeated each time after setting two tiers. 



The 40-ton derrick hoisted material from the street 

 to the platform in about one minute and a half, a 

 distance of about 200 feet. Material was hoisted 

 from the platform, about 350 feet, in three 



