12 inch

Double-Sheave-J-Block

Key to two sheave J-Block Model Numbers

J 5 D 10 B T A
Shorty “J” Crane Block Safe Working Limit-Tons

Number of Sheaves

Double

Sheave Size – Nom. O.D.

Sheave Bearing:

B = Bronze Bushed
R= Roller Bearing

Hook-Thrust Bearing

Cheek Weights:
A = No wts.
AB = Med. wts.
B = Std. wts.
C = X-Heavy wts.


Model WT. A B E F H J K
Overall Net Thick- Width Throat-Opening Hook Hook
Length
Length
ness
w/ Latch
Thick.
Width
J-10D12BTA 165 28.875 26.250 6.125 16 1.91 2.53 1.93
J-10D12BTB 285 28.875 26.250 9.687 16 1.91 2.53 1.93
J-10D12BTC 435 28.875 26.250 14.187 16 1.91 2.53 1.93
J-10D12RTA 165 28.875 26.250 6.125 16 1.91 2.53 1.93
J-10D12RTB 285 28.875 26.250 9.687 16 1.91 2.53 1.93
J-10D12RTC 435 28.875 26.250 14.187 16 1.91 2.53 1.93
J-15D12BTA 170 28.875 26.250 6.125 16 1.91 2.53 1.93
J-15D12BTB 290 28.875 26.250 9.687 16 1.91 2.53 1.93
J-15D12BTC 440 28.875 26.250 14.187 16 1.91 2.53 1.93
J-15D12RTA 170 28.875 26.250 6.125 16 1.91 2.53 1.93
J-15D12RTB 290 28.875 26.250 9.687 16 1.91 2.53 1.93
J-15D12RTC 440 28.875 26.250 14.187 16 1.91 2.53 1.93
J-20D12BTA 225 34.250 30.500 6.625 16 2.80 3.00 2.38
J-20D12BTB 345 34.250 30.500 10.187 16 2.80 3.00 2.38
J-20D12BTC 500 34.250 30.500 14.687 16 2.80 3.00 2.38
J-20D12RTA 225 34.250 30.500 6.625 16 2.80 3.00 2.38
J-20D12RTB 345 34.250 30.500 10.187 16 2.80 3.00 2.38
J-20D12RTC 500 34.250 30.500 14.687 16 2.80 3.00 2.38
J-25D12BTA 225 34.250 30.500 6.625 16 2.80 3.00 2.38
J-25D12BTB 345 34.250 30.500 10.187 16 2.80 3.00 2.38
J-25D12BTC 500 34.250 30.500 14.687 16 2.80 3.00

2.38

J-25D12RTA 225 34.250 30.500 6.625 16 2.80 3.00 2.38
J-25D12RTB 345 34.250 30.500 10.187 16 2.80 3.00 2.38
J-25D12RTC 500 34.250 30.500 14.687 16 2.80 3.00 2.38


Dead End Chart

Wire Rope Size T U For Pin Size
7/16" thru 5/8" 1 1.28 1-1/4
3/4" thru 1" 1.25 1.65 1-5/8
1-1/8" thru 1-3/8" 1.75 2.51 2-1/2

*Gunnebo Johnson Design Factor is 4 to 1, with some exceptions;

45 Ton models 3.6 to 1

60 Ton models 3.7 to 1

325 Ton models 3.7 to 1