Right before the holidays I was finishing up a print job and noticed the the rollers didn’t want to turn with each other anymore. I thought it was the ink drying as a result of the heater blowing close to the press area and didn’t think about it again. After being off for a few weeks, we inked up the press today and are having the same issue. It isn’t as bad, but the rollers are hesitating in the same spots as the move against each other. I have taken off the front form roller to try and identify where the problem is coming from. Everything runs smoothly when the front roller is not there. Everything also seems to run smoothly when there is no ink on the press. I thought maybe my ink was old, so we cleaned the press and put on our freshest can of ink (opened 1 month ago), but it still is an issue.
I tried to switch out the front roller to an old one and the problem still persisted. I have oiled everything and checked to make sure all of the screws are secure.
Per Fritz’s recommendation, I am going to remove the crescent from the ink drum and make sure the stem is well lubricated. I will let you know if that fixes it.
In the mean time, I would love to hear other thoughts. Here is a video: https://vimeo.com/84153721
Hi Anne Marie,
I have had the rider roller checked for straightness and put on new brass bushings a little over a year ago. Supposedly it is fine. The rollers are also only a year old. There is no visible swelling. I had some old rollers on it (with slightly swollen sides) in the past and this wasn’t an issue. The whole thing happened pretty suddenly. It wasn’t a problem one day, and then the next it was.
Thanks for the comment!
Did you happen to try running the press without the rider roller? It looks like it might be bent. Also, I second Jonathon’s observation that this kind of hesitation could be caused by the form rollers swelling at the sides — how are the rollers looking?
Since you said the problem did not occur when the front form roller is out, I would focus on the form rollers and rider roller, rather than the mechanics of the vibrating ink drum.
Thanks for the suggestion Sara L. My core actually has flat spots on both sides of the roller.
Great observation, Sara L! It might be a contributing factor, since the gear is held only by two set screws, instead of a set screw and a woodruff key as on an SP20, Universal or 219. Still, as Fritz pointed out the worm gear points may be chipped.
I don’t know if this is connected to your problem, but it looks like your back form roller is flipped. At about a minute into the video I can see the flat spot on the roller core where the set screw should be holding the gear wheel in place. If the non-operator end of that back form roller core does not have a flat spot for the set screw to push against, there’s a chance the gear wheel is slipping and that may be contributing to how the vibrating drum travels back and forth. I’d trying flipping that back form roller so the flat spot on the core aligns with the set screw in the gear wheel.
to me it looked on the video that the front roller was shrunk in the middle and ink not even along its length, ie hollow, would that make a difference as the ink cylinder traverses????????????
The next thing I suggested to Sarah was to take the vibrating ink drum and reverse its position, with the worm on the non-operator’s side. I tried it on our SP-15 first and it works fine. Sarah reported back that there is still the momentary hesitation with the ink drum so my thought is the problem is in the crescent/worm. There could be a small chip on one of the points of the worm, or the crescent has become too worn to track properly. The worm is hardened steel, so resists filing to clean up the points and down the road, she may need a new worm. So, add to the list of things I need to spring for. The pattern still exists and these are lost wax steel castings with a hefty minimum order, but we will be in trouble if there is not a new supply available. But like any of the other Vandercook parts I regularly have made, keeping parts in inventory is critical for these presses.
Following up… I cleaned out the crescent and made sure the stem was well lubricated. The problem is still happening.