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
Quadruple

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-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