HOW TO FIGURE OVERHAULING WEIGHTS

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This is a conservative method of approximating the load block weight required to overhaul the wire rope properly on crane applications.
crane
TAKE:  Approximate weight of wire rope on backside of boom (Table A: x boom length)   
    +       Pull required to overcome friction of hoist drum (nominally 100 pounds)
    x       Overhaul factor for number of load lines (Table B)
    =       
Required weight of load block

TABLE A: WIRE ROPE WEIGHT TABLE B: OVERHAUL FACTORS
SIZE LBS. PER FT.,
6 X 19 WRC
NO.
LINES
ROLLER BEARING
SHEAVES
BRONZE BUSHED
SHEAVES
3/8 .26 1 1.03 1.05
7/16 .36 2 2.07 2.14
1/2 .46 3 3.15 3.28
9/16 .59 4 4.25 4.48
5/8 .72 5 5.38 5.72
3/4 1.04 6 6.54 7.03
7/8 1.42 7 7.73 8.39
1 1.85 8 8.94 9.80
1-1/8 2.34 9 10.20 11.30
1-1/4 2.89 10 11.50 12.80

EXAMPLE:
5 Parts 7/8" wire rope. 50' boom, roller bearing sheaves.
Required Weight = [A(50) + 100] B =[1.42(50) + 100] 5.38 = (171) 5.38 = 920 Ibs.