I’ve been having some problems with the oscillating roller on my 320G. It would stop rolling and begin to chatter as the cylinder traveled across the bed. When the cylinder changed direction it would begin to roll normally again. I think this condition was caused by the worm gear and/or crescent. I adjusted the screw that covers the crescent and lubricated the gear. That seemed to help but didn’t totally correct the problem. The cylinder would travel 8 or 9 times with the oscillating roller working properly then all of a sudden the oscillating roller assembly would jump off the roller assembly. When I put it back on it works fine again for 8 or 9 trips then jumps off again. I don’t know what is going on. Any help would be greatly appreciated.
I have tried to take the crescent out so I could exam it but I can’t figure out how to do that. I took the set screw out (the one with the allen head, in the end of the roller) and I removed the screw that covers the crescent. There is a slot at the end of the oscillating roller that seems like the crescent should fit through but i can’t get it out. Can someone tell me how to remove the crescent? Any help would really be appreciated.
The post of the crescent must be perfectly aligned with the slot, and the slot must be free and clear of dried ink. Then it’s just a matter of lining up the post with the hole and sliding. You must have the post and roller all the way to the worm end of the movement or there won’t be enough room to shift away.
The bad effect of worn worm-and-crescent can be amplified by use of tacky ink such as rubber base, and especially older rubber base. It takes a lot more energy to split the ink film between thje rollers, and the worn press parts aren’t up to the job. Rubber base ink should always be loosened up by working with a knife on the slab before it is put on press, and sometimes reducer may be needed. Oil base ink will usually be less tacky.