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20 inch

Triple-Sheave-J-Block

Key to three sheave J-Block Model Numbers

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

Number of Sheaves

T=3
Triple

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
J30T20BTA 675 42.125 38.375 12 24.75 3.28 3.50 3.00
J30T20BTB 976 42.125 38.375 14.375 24.75 3.28 3.50 3.00
J30T20BTC 1320 42.125 38.375 19.375 24.75 3.28 3.50 3.00
J30T20RTA 675 42.125 38.375 12 24.75 3.28 3.50 3.00
J30T20RTB 976 42.125 38.375 14.375 24.75 3.28 3.50 3.00
J30T20RTC 1320 42.125 38.375 19.375 24.75 3.28 3.50 3.00
J35T20BTA 738 42.125 38.375 12 24.75 3.27 4.25 3.38
J35T20BTB 1039 42.125 38.375 14.375 24.75 3.27 4.25 3.38
J35T20BTC 1383 42.125 38.375 19.375 24.75 3.27 4.25 3.38
J35T20RTA 738 42.125 38.375 12 24.75 3.27 4.25 3.38
J35T20RTB 1039 42.125 38.375 14.375 24.75 3.27 4.25 3.38
J35T20RTC 1383 42.125 38.375 19.375 24.75 3.27 4.25 3.38
J40T20BTA 869 51.125 46.875 12 24.75 3.27 4.25 3.38
J40T20BTB 1169 51.125 46.875 14.375 24.75 3.27 4.25 3.38
J40T20BTC 1513 51.125 46.875 19.375 24.75 3.27 4.25 3.38
J40T20RTA 869 51.125 46.875 12 24.75 3.27 4.25 3.38
J40T20RTB 1169 51.125 46.875 14.375 24.75 3.27 4.25 3.38
J40T20RTC 1513 51.125 46.875 19.375 24.75 3.27 4.25 3.38
J45T20BTA 869 51.125 46.875 12 24.75 3.27 4.25 3.38
J45T20BTB 1169 51.125 46.875 14.375 24.75 3.27 4.25 3.38
J45T20BTC 1513 51.125 46.875 19.375 24.75 3.27 4.25 3.38
J45T20RTA 869 51.125 46.875 12 24.75 3.27 4.25 3.38
J45T20RTB 1169 51.125 46.875 14.375 24.75 3.27 4.25 3.38
J45T20RTC 1513 51.125 46.875 19.375 24.75 3.27 4.25 3.38
J55T20BTA 949 55.500 49.375 12.750 24.75 4.63 6.13 4.00
J55T20BTB 1250 55.500 49.375 14.375 24.75 4.63 6.13 4.00
J55T20BTC 1594 55.500 49.375 19.375 24.75 4.63 6.13 4.00
J55T20RTA 949 55.500 49.375 12.750 24.75 4.63 6.13 4.00
J55T20RTB 1250 55.500 49.375 14.375 24.75 4.63 6.13 4.00
J55T20RTC 1594 55.500 49.375 19.375 24.75 4.63 6.13 4.00
J60T20BTA 949 55.500 49.375 12.750 24.75 4.63 6.13 4.00
J60T20BTB 1250 55.500 49.375 14.375 24.75 4.63 6.13 4.00
J60T20BTC 1594 55.500 49.375 19.375 24.75 4.63 6.13 4.00
J60T20RTA 949 55.500 49.375 12.750 24.75 4.63 6.13 4.00
J60T20RTB 1250 55.500 49.375 14.375 24.75 4.63 6.13 4.00
J60T20RTC 1594 55.500 49.375 19.375 24.75 4.63 6.13 4.00
J65T20BTA 982 55.750 49.500 12.750 24.75 4.36 6.25 4.50
J65T20BTB 1282 55.750 49.500 14.375 24.75 4.36 6.25 4.50
J65T20BTC 1626 55.750 49.500 19.375 24.75 4.36 6.25 4.50
J65T20RTA 982 55.750 49.500 12.750 24.75 4.36 6.25 4.50
J65T20RTB 1282 55.750 49.500 14.375 24.75 4.36 6.25 4.50
J65T20RTC 1626 55.750 49.500 19.375 24.75 4.36 6.25 4.50
J70T20BTA 982 55.750 49.500 12.750 24.75 4.36 6.25 4.50
J70T20BTB 1282 55.750 49.500 14.375 24.75 4.36 6.25 4.50
J70T20BTC 1626 55.750 49.500 19.375 24.75 4.36 6.25 4.50
J70T20RTA 982 55.750 49.500 12.750 24.75 4.36 6.25 4.50
J70T20RTB 1282 55.750 49.500 14.375 24.75 4.36 6.25 4.50
J70T20RTC 1626 55.750 49.500 19.375 24.75 4.36 6.25 4.50
J75T20BTA 1190 60 53 12.875 24.75 4.75

6.75

 4.75
J75T20BTB 1492 60 53 15.625 24.75 4.75 6.75 4.75
J75T20BTC 1836 60 53 20.625 24.75 4.75 6.75 4.75
J75T20RTA 1190 60 53 12.875 24.75 4.75 6.75 4.75
J75T20RTB 1492 60 53 15.625 24.75 4.75 6.75 4.75
J75T20RTC 1836 60 53 20.625 24.75 4.75 6.75 4.75
J80T20BTA 1190 60 53 12.875 24.75 4.75 6.75 4.75
J80T20BTB 1492 60 53 15.625 24.75 4.75 6.75 4.75
J80T20BTC 1836 60 53 20.625 24.75 4.75 6.75 4.75
J80T20RTA 1190 60 53 12.875 24.75 4.75 6.75 4.75
J80T20RTB 1492 60 53 15.625 24.75 4.75 6.75 4.75
J80T20RTC 1836 60 53 20.625 24.75 4.75 6.75 4.75


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