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12 inch

Single-Sheave-J-Block


Key to one sheave J-Block Model Numbers

J 3 S 10 B T A
Shorty “J” Crane Block Safe Working Limit-Tons

Number of Sheaves

Single

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- Throat
Opening		 Hook Hook
Length Length ness Width w/Latch Thick. Width
J-5S12BTA 135 30.375 24.875 6.187 16 1.39 1.81 1.38
J-5S12BTB 255 30.375 24.875 9.687 16 1.39 1.81 1.38
J-5S12BTC 410 30.375 24.875 14.187 16 1.39 1.81 1.38
J-5S12RTA 135 30.375 24.875 6.187 16 1.39 1.81 1.38
J-5S12RTB 255 30.375 24.875 9.687 16 1.39 1.81 1.38
J-5S12RTC 410 30.375 24.875 14.187 16 1.39 1.81 1.38
J-10S12BTA 145 32.500 26.250 6.187 16 1.91 2.53 1.93
J-10S12BTB 270 32.500 26.250 9.687 16 1.91

2.53

 1.93
J-10S12BTC 420 32.500 26.250 14.187 16 1.91 2.53 1.93
J-10S12RTA 145 32.500 26.250 6.187 16 1.91

2.53

 1.93
J-10S12RTB 270 32.500 26.250 9.687 16 1.91 2.53 1.93
J-10S12RTC 420 32.500 26.250 14.187 16 1.91 2.53 1.93
J-15S12BTA 140 32.500 26.250 6.437 16 1.91 2.53 1.93
J-15S12BTB 263 32.500 26.250 9.687 16 1.91 2.53 1.93
J-15S12BTC 415 32.500 26.250 14.187 16 1.91 2.53 1.93
J-15S12RTA 140 32.500 26.250 6.437 16 1.91 2.53 1.93
J-15S12RTB 263 32.500 26.250 9.687 16 1.91 2.53 1.93
J-15S12RTC 415 32.500 26.250 14.187 16 1.91 2.53 1.93
J-20S12BTA 200 37.875 30.500 6.687 16 2.80 3.00 2.38
J-20S12BTB 323 37.875 30.500 10.187 16 3.500 3.00 2.38
J-20S12BTC 475 37.875 30.500 14.687 16 2.80 3.00 2.38
J-20S12RTA 200 37.875 30.500 6.687 16 2.80 3.00 2.38
J-20S12RTB 323 37.875 30.500 10.187 16 2.80 3.00 2.38
J-20S12RTC 475 37.875 30.500 14.687 16 2.80 3.00 2.38

*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