The reversing sub is also called reversing spear which is a special tool for reversing stuck drill stem above stuck point in drilling and work over operation. In treatment of stuck drill stem, it can work as a fishing pin tap in reversing operation. When fish is stuck or can not be reversed in fishing or reversing operation, the fish can be reversed from reversing sub and the fishing drill tool can be tripped out.

Technical parameters and specifications

 

O.D.		Thread connection	Fishing thread (KN)	Tensile Strength (KN)	Torsion Strength (KN.m)
mm	in
105	2 7/8	2 7/8IF	2 7/8IF	500	9
120	3 1/2	NC38	NC38	900	15
156	4 1/2	NC50	NC50	1500	35
178	5 1/2	5 1/2FH/NC50	5 1/2FH	2000	50
197	6 5/8	6 5/8REG	6 5/8REG	2500	65