What is the Difference between Cougar’s DJ6 Jar and DJ4 Jar?
A3: The DJ6 is a Hydraulic–Mechanical Drilling Jar whereas the DJ4 is strictly hydraulic. What this means is that the DJ6 uses a mechanical locking mechanism to prevent firing. When operating a DJ6, the mechanical lock must be overcome before the hydraulic section will meter. The DJ4 uses a hydraulic lock. The force applied to the jar creates pressure internally in the tool. Once this pressure exceeds a specified amount, the lock releases and the tool meters hydraulically. Another key difference is that the DJ6 is double acting. This means that it can be fired up or down. The DJ4 can only be fired up, but it can be used as a bumper sub to bump down.
