12 inch

Key to four sheave J-Block Model Numbers
J | 15 | Q | 10 | B | T | A |
Shorty “J” Crane Block | Safe Working Limit-Tons |
Number of Sheaves Q=4 |
Sheave Size – Nom. O.D. |
Sheave Bearing: B = Bronze Bushed |
Hook-Thrust Bearing |
Cheek Weights: |
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-20Q12BTA | 320 | 29.750 | 26.750 | 11.125 | 16 | 2.80 | 3.00 | 2.38 |
J-20Q12BTB | 440 | 29.750 | 26.750 | 14.750 | 16 | 2.80 | 3.00 | 2.38 |
J-20Q12BTC | 595 | 29.750 | 26.750 | 19.250 | 16 | 2.80 | 3.00 | 2.38 |
J-20Q12RTA | 320 | 29.750 | 26.750 | 11.125 | 16 | 2.80 | 3.00 | 2.38 |
J-20Q12RTB | 440 | 29.750 | 26.750 | 14.750 | 16 | 2.80 | 3.00 | 2.38 |
J-20Q12RTC | 595 | 29.750 | 26.750 | 19.250 | 16 | 2.80 | 3.00 | 2.38 |
J-25Q12BTA | 320 | 29.750 | 26.750 | 11.125 | 16 | 2.80 | 3.00 | 2.38 |
J-25Q12BTB | 440 | 29.750 | 26.750 | 14.750 | 16 | 2.80 | 3.00 | 2.38 |
J-25Q12BTC | 595 | 29.750 | 26.750 | 19.250 | 16 | 2.80 | 3.00 | 2.38 |
J-25Q12RTA | 320 | 29.750 | 26.750 | 11.125 | 16 | 2.80 | 3.00 | 2.38 |
J-25Q12RTB | 440 | 29.750 | 26.750 | 14.750 | 16 | 2.80 | 3.00 | 2.38 |
J-25Q12RTC | 595 | 29.750 | 26.750 | 19.250 | 16 | 2.80 | 3.00 | 2.38 |
J-30Q12BTA | 355 | 33.250 | 29.500 | 11.250 | 16 | 3.28 | 3.50 | 3.00 |
J-30Q12BTB | 475 | 33.250 | 29.500 | 14.750 | 16 | 3.28 | 3.50 | 3.00 |
J-30Q12BTC | 630 | 33.250 | 29.500 | 19.250 | 16 | 3.28 | 3.50 | 3.00 |
J-30Q12RTA | 355 | 33.250 | 29.500 | 11.250 | 16 | 3.28 | 3.50 |
3.00 |
J-30Q12RTB | 475 | 33.250 | 29.500 | 14.750 | 16 | 3.28 | 3.50 | 3.00 |
J-30Q12RTC | 630 | 33.250 | 29.500 | 19.250 | 16 | 3.28 | 3.50 |
3.00 |
J-35Q12BTA | 419 | 39 | 34.750 | 11.250 | 16 | 3.27 | 4.25 | 3.38 |
J-35Q12BTB | 540 | 39 | 34.750 | 14.750 | 16 | 3.27 | 4.25 | 3.38 |
J-35Q12BTC | 692 | 39 | 34.750 | 19.250 | 16 | 3.27 | 4.25 | 3.38 |
J-35Q12RTA | 419 | 39 | 34.750 | 11.250 | 16 | 3.27 | 4.25 | 3.38 |
J-35Q12RTB | 540 | 39 | 34.750 | 14.750 | 16 | 3.27 | 4.25 | 3.38 |
J-35Q12RTC | 692 | 39 | 34.750 | 19.250 | 16 | 3.27 | 4.25 | 3.38 |
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