Finger tight is no good! I dislike using pliers as it can damage the ER. A drill press's chuck has no teeth inside and will not mar the ER. Tighten the chuck with the key just enough that the ER will not spin in the chuck.
I use a Drill Press's chuck (not clamped on the knurled portion - push that area in past the jaws) to grip the ER. Place 3 empties in from the bottom and hold the chuck with one hand while tightening the cylinder with the other. The empties keep the two alignment pins from getting damaged while tightening. Remember that the thread is reverse (left handed) on that model and while it should be securely tightened, never "Gorilla tighten" it.
If you do not have a drill press, a regular unplugged electric drill can be used also. If using a battery operated drill, remove the battery so it doesn't accidentally spin.
If you have some basic mechanical skills you might want to unscrew the ER all the way, disassemble and then clean all springs and parts (including the cylinder's tunnel) before reassembling. Lightly lubricate before assembling.