15-21, roller issue

This may prove painfully obvious, but here are the details of my issue, which I’m hoping someone out there may be able to help me with.

Running a sheet through the press over a 2-page spread of metal type, head to foot, without ink I’m getting a good, clean, even impression.

I then set my rollers with a .918 gauge to between 1/16 and 1/8 strip at each corner (lft/frnt, lft/rear, right/frt, right rear).

I then run a sheet through, and the left page (closest to operator) inks relatively well, but the right page gets hardly any ink at all. In order to get even inking, I have to lower both rollers on the non-operator side until I’m getting almost a 1/4 inch on the gauge.

This makes no sense at all. Any ideas?

ps. I should also mention that when inking up the press, with the rollers set evenly with the gauge, I’m getting very little contact from the drum to the rubber rollers to the triple-metal rollers on top. I find I have to press down on the triple-metal-roller rack on the non-operator side in order to get good contact and thus good ink distribution on all rollers.


20 thoughts on “15-21, roller issue

  1. Eric Holub - June 17, 2011

    Well, I guess removing the front form would be way too much work, and even raising it would be an unnecessary coplication. Easy in SPs and Universals, not here. Just remove the distributors and examine how drum, form rollers, and plate relate to each other in motion.
    It also struck me that this probably was designed for nyliners. Are they all present? Missing nyliners would mean play or false motion at the roller ends.

  2. Jason Dewinetz - June 17, 2011

    Eric, when you say “remove the front roller,” do you mean take it right out of the frame? Or just raise it up so that it has no contact with the form?

    And, yes, it’s a .918 gauge.

  3. Jason Dewinetz - June 17, 2011

    Hi Fritz,

    I only have two diagrams, which you sent me a few years ago: No. 176 & 177. Could I bother you to send me a scan of the drawing for the form rollers & the rider/oscillator roller assembly? I’d like to have a clearer idea of how the riders are put together.

    To add to the discussion, fairly often (but especially once the ink sets up a bit) and I have the rollers set for light inking, as the oscillator moves back and forth, I get quite a rumble; that is, the rider-rollers seem to bind a bit and thus cause the entire assembly to vibrate quite aggressively. Perhaps this is because my rider rollers weren’t spinning as easily as they should, so I’ll see how things roll the next time I ink up (having oiled the riders yesterday). But I wonder if this information might add something to the comments you & Eric have kindly offered so far.

  4. Fritz Klinke - June 17, 2011

    The wood bearing in the ends of the rider rollers is F-761. These were designed not to be lubricated as the wood used is self lubricating, but they do wear out after time and should be replaced. It means the taper pins holding the assembly together have to be removed to access the rider rollers to replace the bearings. We can also offer a newer plastic bearing material made to the same specifications as the original wood. The other thing to check for wear is the bearing block on each end of the ink rollers.

  5. Eric Holub - June 16, 2011

    I’d try to isolate things. Ink up, but then remove the distributors and front form roller. Does the rear form roller by itself still fail to ink the same place in the form? Can you see anything lifting as the roller crosses the form?
    If the form is level and stable, but the roller fails to contact, is there is some roller lift happening?
    If it doesn’t happen with one roller, add the front form and see if anything changes, and if not, then add the distributors.
    Sometimes it can be as simple as a loose screw somewhere. But why the rollers on one side need to be lowered below .918 is strange.
    It can’t be a .968 gauge can it?

  6. Jason Dewinetz - June 16, 2011

    Hi Eric,

    Yes, some oil into the riders has helped, and has also, as you warned, gotten into the ink; not a problem today as I’m simply doing maintenance.

    I’ve spent the last four hours on the bearings, and have them set as you’ve described: snug (but not tight) against the top on Print, and adjusted on the bottom in Trip until the form rollers are giving me quite similar results on the ink gauge.

    However, my original problem persists: in order to get even inking on a print, I have to have the form rollers lowered on the non-operator side until they are much lower than the operator side. What boggles me is that this isn’t only evident on the print: I have two polymer plates in right now, full pages of text, on the same base, and after cleaning them off, then running the carriage over once in Trip to ink them, the right (non-operator) plate gets very little ink, despite the fact that I’ve just set the rollers with the gauge also on Trip!

    I’ve had it for today, so I’m going to clean everything up and have another go at it tomorrow.

  7. Paul Moxon, Moderator - June 16, 2011

    Jason, You’re on the right track, 20lb. copy paper is .004″. I think you should only need to adjust the number 4 bearings.

    As is often the case, the problem may have more than one source. It’s still likely that one or more of the tie rods on the form roller frame are bent.

    About the riders: I’ve lubricated them by dabbing Vaseline on the edge of card stock–and sometimes floss.

    Also, this is inconsequential, but the oscillator tube should be rotated so that the worm gear is on the operator’s side. Obviously it works in either orientation, but when you can see it you’re more likely to lubricate it.

  8. Eric Holub - June 16, 2011

    It seems to me that the impression bearings should be set against the rails above them (while on impression), to keep the cylinder from lifting off on impression. The trip bearings should be set against the rails below them (while on trip), and since they control carriage height they also control roller height on trip. These may not be set in the proper direction or at the correct timing.
    Once you get the impression bearings set correctly, re-set the roller height, then adjust the trip bearings until rollers ride at same level on both trip and print. Or, in practice, until close enough.
    It is something that can drive you crazy.
    The riders could use a small amount of lubrication, perhaps a drop of gear oil placed with a needle, at long intervals. Too much oil or a thin oil, and it will get into the ink train.

  9. Jason Dewinetz - June 16, 2011

    In Print mode, mid-bed, I can just pull a piece of 20lb bond paper under the 2 and 4 (Trip) bearings on the non-operator side, and doing so causes these bearings to turn. This seems to suggest these two bearings are set correctly.

    On the operator side I can pull the paper through on bearing 1 and it turns from friction, but on 4 I can pull the paper through without any friction on the bearing (it doesn’t turn). This would seem to suggest that I need to lower the 4 bearing on the operator side slightly.

    However, the amount is so small that I can’t see this fixing the discrepancy between my ink strips on Print (1/16) and Trip (3/8).

    But, lowering the Trip bearings any further would create full contact of all 8 bearings when in Print mode, which I don’t think is correct.

  10. Jason Dewinetz - June 16, 2011

    Eric, there’s definitely an issue with the carriage bearings: I just checked the ink strip on the gauge on Trip and on Print. After setting the rollers on Print to 1/16″ strip, then checking on Trip, the strip is MUCH thicker on Trip (around 3/8″).

    There are four sets of carriage bearings on the 15-21, two upper for Print mode, and two lower for Trip. Attached is an image from the side. From this view the bearings are: 1 Print, 2 Trip, 3 Print, 4 Trip.

    My guess is that the number 4 bearings on each side are set too HIGH, thus lowering the foot-end of the carriage when in Trip, and thus resulting in a much thicker ink strip on the guage.

    Is it this simple (relatively speaking)? Or will it involve realigning all of the Trip bearings, or, worse, all 8 bearings?

  11. Jason Dewinetz - June 16, 2011

    Here’s the other image…

  12. Jason Dewinetz - June 16, 2011

    Eric, here are a couple of images of the rider assembly. You’ll see that the riders are on solid cores which are mounted through the brass frame ends. If these are meant to be lubricated, it’s not very easy to get oil between the end of the roller and the brass frame, let alone all the way through the roller. As I say, they used to turn much easier than they do these days; I would think this is due to ink residue getting down into the space between the core/axel and the roller.

    I’m inking up to do some printing today and am going to check the form rollers both on Trip and Print and will report back here.

  13. Eric Holub - June 15, 2011

    Most riders are tubular steel; some may rotate on shafts (I think the No. 4 does) or stubs (Universals, and on some SPs they may use nyliners); others have caps with a journal protruding, and that is inserted into the side of the distributor frame. I don’t know what is on the 15-21. On the 219 series, the OS models have no bushings, and so the frame pieces themseves wear out. On the NS series, there are bronze bushings inserted in the frame to receive the rider journals. When those wear, the bushings can be presssed out and new bushings inserted.
    For the riders to not turn freely, I’d think it was either lack of lubrication, or they are binding up from contact against the frame (and that could happen if it were warped or twisted), or buildup of dried ink.

  14. Jason Dewinetz - June 15, 2011

    Hi Eric,
    I don’t have a surface gauge, but I’ve done a few things to check the height of the drum, and it appears to be level.

    Good call to gauge the form rollers on both Trip and Print: out of habit I always set them on Trip. I’ll check both the next time I have ink on the press.

    As for your comment on distributor frame bushings, could you tell me a bit more about this/these?

    The two smaller metal rollers are quite stiff in their turning, which was not the case in the past. A quick pull of the hand over the roller used to have them spin quite freely, whereas now I get maybe one rotation (my oscillating distributor turns very freely and smoothly). What is inside these small metal rollers? The assembly certainly isn’t heavy enough for all three to be solid steel, so I would imagine they are wood wrapped in metal with a whole drilled out for the core/axel? Is it possible that the wood (or whatever is in there) could swell and thus add drag to the rotation? Not sure if this has anything to do with my current issue, but I’ve wondered about this for a while now.

  15. Eric Holub - June 15, 2011

    I’d start from the drum and work up the ink chain. A surface gauge set on the bed with Dial indicator on the drum can tell you if the drum is out of parallel with the bed. If that’s OK, why does the ink not transfer consistantly to the form rollers? Is there something that causes them to change position with carriage movement? Mis-set bearings, top or bottom, could affect this (at least on SPs and Universals, not sure how the 15-21 is designed) so I’d check with the roller gauge to see that the stripe is the same on trip and on print. Problems with distributors would be more common (twisted, worn, etc.) but ink should still transfer from drum to rear form no matter what else is happening.
    The No. 4 does have an adjustment to skew the distributor frame, and if this has one too I’d check that. The distributor frame may also have worn bushings, which can let a distributor sag out of contact. By the time of the 15-21 they should have replaceable bronze bushings.

  16. Jason Dewinetz - June 14, 2011

    The problem isn’t with the type Dafi, as the same issue happens when printing from polymer on a Boxcar base, thus the printing surface is good and flat at .918.

    Steve, I’m curious about your comment regarding the rider roller assembly. I’ll pull that off and test how true it is; the small metal roller closest to the cylinder has some resistance when turning, so something there might be out of alignment.

    I’ll hope it’s not the carriage bearings. I adjusted them quite a while ago (5 or 6 years), but you’re right, they could have worked their way out of alignment. I’ve noticed some very dark residue on the rails on the non-operator side for the past few months (the bed rail and the upper rail for the lower bearings), which I hope has not been metal.

  17. Dafi - June 14, 2011

    This could be another problem:

    Is the your type on the pressbed locked properly and not too tight?
    If it is locked too tight or the typesetting is not too accurate, the type could get lifted up at some point, which causes the bad inking at some areas.
    That means: The impression just with the cylinder was enough to push the type down to the pressbed, which explains why you seem to have an even impression. As soon as the cylinder doesn’t touch the type anymore, it will get lifted up. The rollers might not have enough impression to push down the type…
    Try losen the type, vibrate it down and do not lock it too tightly just for some testprints…
    I dont want to tell you, that your typesetting is bad, its just a problem that sometimes might happen, especially with woodtype or lots of different fonts in the same block…

    sure it could still be something with the press…

    hope this helps.
    good luck. dafi

  18. Steve Robinson - June 14, 2011

    If the cylinder carriage bearings are out of adjustment it is possible the far side is lifting slightly once impression is engaged and a sheet “squeezed” through. Have you checked the roller stripes with impression on?

    The rider roller assembly could be skewed (they sometimes get dropped), have you placed it on your composing stone to determine how “true” the assembly is?

  19. Jason Dewinetz - June 13, 2011

    Hi Paul,
    The rollers are good, less than six months old, three full inches at all ends (just checked with calipers).

  20. Paul Moxon, Moderator - June 13, 2011

    The poor contact with the oscillator suggests that the rubber has shrunk. Use calipers to check the roller diameter, which should be 3″.

Leave a Reply

Copyright © 2022 vandercookpress.infoTheme by SiteOrigin
Scroll to top