168 



BULLETIN 711, U. S. DEPAETMElsTT OF AGEICtJLTTJEE. 



This block is adapted for gin-pole or overhead loading. 

 The blocks listed below are adapted for any work where blocks 

 are himg in an overhead position and frequent oiling is impossible 

 without great loss of time. They are of the auto-lubricating type. 

 The sheaves are made of manganese steel. 



Prices of blocks. 



No. 



Sheave. 



Bearing. 



Diame- 

 ter pla. 



Weight. 



Net 

 price. 



1 



Inches. 

 12 by 2 

 14 by 2 

 18 by 2J 

 24 by 3 

 24 by 5 

 36 by 3 



Inches. 

 3 

 3 



^ 



5 



7 

 8 



Inches. 

 2i 

 21 

 3 



Z\ 

 31 

 3i 



Pounds. 

 115 

 150 

 230 

 410 

 450 

 750 



$27.00 







34.00 



3 



50.00 



4 



81.00 



5 



90.00 



6 



144.00 







TREE JACK. 



Figure 46 is a cut of one of the types of tree jacks. They are 

 designed for extremely heavy duty, such as is found in overhead 

 loading and yarding. They are easy on the lines, since the strain 

 is equally divided on the three sheaves, the same results being se- 

 cured as with an extremely large sheave. The size and net selling 

 prices f. o. b. Portland, Tacoma, or Seattle in March, 1916, were as 

 follows : 



Tree jacks. ' 



No, 



Size of 

 sheaves. 



Net sell- 

 ing price 



with 

 manga- 

 nese-steel 

 sheaves. 



1 



Inches. 

 10 by 3 

 14 by 3 

 16 by 3 

 9 by 7 

 14 by 6i 

 16 by 9 



$67. 50 



2 



78.75 



3 ... . 



90.00 



4 



82.50 



5 . 



93.75 



6 



114.00 







Spares. 



Item. 



Net price. 



No. 1. No. 2. No. 3. No. 4. No. 5. No. 6. 



Pair forged sides 



Bronze bushed mangancsc-stool sheaves. . 



Shackle and pin 



Set of three pins 



Bronze bushing 



S22. 50 

 9.75 

 .5.25 

 6.80 

 2.65 



$25. 50 

 13. 50 

 6.00 

 6.80 

 2.65 



$27.00 



15.00 



6.00 



7.30 



2.65 



$22. 50 

 15.00 

 5.25 

 6.80 

 3.40 



$25.50 



18.00 



6.30 



8.00 



3.75 



$27.00 



24.00 



6.80 



9.00 



5.25 



LOADING LINES. 



The selling price of wire rope is discussed under " Ground yard- 

 ing." The length and size of lines used are dealt with under 

 " Methods "in this section. 



