vandercook rollers skipping

What I mean is, the gear at the end of the form roller gets hung up and skips and bounces as the cylinder travels down the bed of the press, producing a mighty crappy image. I thought it had to do with ink running too long on the press, getting too sticky and causing the roller to drag and stick, but now I’m not so sure, since I just cleaned everything and started from scratch and it’s still doing it. On the other hand, it’s really cold in the garage this morning, which may be a factor. I’ve had my press about 6 years, and it seems to be getting worse. It’s not predictable; one day it sucks, the next everything is smooth sailing. I’m using Van Sons Rubber Base. Any ideas? Thanks! Cory

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Cory

It may be as simple a fix as adjusting your rollers. Usually any noise associated with the gear is eliminated with roller adjustment.

Normally, I’d think your ink was too stiff or drying out but with Van Sons that doesn’t seem likely. Temperature might as well be a factor. You may also be rolling the cylinder too fast.

It could also be that the gear is not fitted tight, or correctly, to the form roller.

Gerald
http://BielerPress.blogspot.com

I think the gear not fitting properly *is* part of the problem. I adjusted the rollers as part of my troubleshooting, and that didn’t fix it, alas. I have been able to solve the problem in the past by rolling the cylinder very gently and smoothly, but increasingly that doesn’t do the trick either. I think it’s the accumulation of a bunch of little wrongnesses: the bearing assembly (is that the right term?) at the end of the roller, beyond the gear, which has never fit quite right; one of the form rollers is a little chewed up, the press bed is a plate of metal which isn’t quite the correct height, and there are a bunch of little loosenesses and wiggles, and so the increased viscosity of the ink on bitterly cold days is the last straw and the press acts up. Gah! Time for an overhaul. Gah! Thanks for the response, Cory

Cory:

Inspect the geared running rail that meshes with the gear of the form roller. These can be impacted with grit, oil, dried ink and dirt and an occassional thin spacer. Solvent and a toothbrush sized wire brush will do the job. The dried gunk can interfere with the smooth tracking as you bring the head forward. Also, are the teeth intact? Rarely, but worth the effort, inspect your rollers to be sure there is no shrinkage anywhere along the core. If they are out of round rollers can chatter (vibrate). I assume they are rubber rollers.

Vance Studley

You have two issues at play, Rubber Base Plus going tacky combined with cold temperature.

As my SP15 lives in my dining room, I can say that even though I favour RBP as my ink of choice, it WILL become increasingly tacky over the course of a few days and will cause the skipping you describe. I usually give the ink distribution cylinder a spritz with Van Son Anti-Skin to “wake up” the ink and that aleviates the problem. Less than a full pump stroke is needed. Use sparingly.

Since you say you have washed up and re-inked, I would conclude that the cold temperature is the cause in your instance. Try warming the inking mechanism up by whatever means is safe and see how you fare. A quartz heater might work.

mjb