12 inch

Key to five sheave J-Block Model Numbers

J	25	QN	10	B	T	A
Shorty “J” Crane Block	Safe Working Limit-Tons	Number of Sheaves QN=5 Quintuple	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.

Shorty “J” Crane Block

Safe Working Limit-Tons

Number of Sheaves

QN=5
Quintuple

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.

*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