20 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 T U
Overall Net Thick- Throat Opening Hook Hook Deadend Hole
Length Length ness Width w/Latch Thick. Width Thick. Dia.
J25S20BTA 434 49.750 40.875 8.562 24.750 3.28 3.750 3 1.50 2.06
J25S20BTB 734 49.750 40.875 11.437 24.750 3.28 3.750 3 1.50 2.06
J25S20BTC 1078 49.750 40.875 16.437 24.750 3.28 3.750 3 1.50 2.06
J25S20RTA 434 49.750 40.875 8.562 24.750 3.28 3.750 3 1.50 2.06
J25S20RTB 734 49.750 40.875 11.437 24.750 3.28 3.750 3 1.50 2.06
J25S20RTC 1078 49.750 40.875 16.437 24.750 3.28 3.750 3 1.50 2.06
J30S20BTA 448 50.250 41.375 8.562 24.750 3.28 3.50 3 1.50 2.06
J30S20BTB 748 50.250 41.375 11.437 24.750 3.28 3.50 3 1.50 2.06
J30S20BTC 1092 50.250 41.375 16.437 24.750 3.28 3.50 3 1.50 2.06
J30S20RTA 448 50.250 41.375 8.562 24.750 3.28 3.50 3 1.50 2.06
J30S20RTB 748 50.250 41.375 11.437 24.750 3.28 3.50 3 1.50 2.06
J30S20RTC 1092 50.250 41.375 16.437 24.750 3.28 3.50 3 1.50 2.06
J35S20BTA 528 54.750 44.625 8.562 24.750 3.27 4.250 3.38 1.75 2.28
J35S20BTB 828 54.750 44.625 11.437 24.750 3.27 4.250 3.38 1.75 2.28
J35S20BTC 1172 54.750 44.625 16.437 24.750 3.27 4.250 3.38 1.75 2.28
J35S20RTA 528 54.750 44.625 8.562 24.750 3.27 4.250 3.38 1.75 2.28
J35S20RTB 828 54.750 44.625 11.437 24.750 3.27 4.250 3.38 1.75 2.28
J35S20RTC 1172 54.750 44.625 16.437 24.750 3.27 4.250 3.38 1.75 2.28
J40S20BTA 648 59 46.875 9.437 24.750 3.27 4.250 3.38 1.75 2.28
J40S20BTB 947 59 46.875 12.187 24.750 3.27 4.250 3.38 1.75 2.28
J40S20BTC 1291 59 46.875 17.187 24.750 3.27 4.250 3.38 1.75 2.28
J40S20RTA 648 59 46.875 9.437 24.750 3.27 4.250 3.38 1.75 2.28
J40S20RTB 947 59 46.875 12.187 24.750 3.27 4.250 3.38 1.75 2.28
J40S20RTC 1291 59 46.875 17.187 24.750 3.27 4.250 3.38 1.75 2.28

*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