“Seesaw” Inking on C&P
The strangest thing is happening with my inking and I would love some thoughts from people.
Let me start at the beginning:
We recently acquired a 10x15 old style C&P. Once we got our brand new rubber rollers, we used our roller gauge to meticulously tape the very uneven rails, adding where the rollers where low, taking away where it was higher, etc. Then we locked up our deep relief Boxcar base and got to work.
This produced very unpredictable results. I have seem many posts describing a similar effect with the boxcar base — areas over inking then disappearing 10 prints later etc. We were adjusting the tape on our rails every 5-10 prints and losing our minds!
One solution mentioned many times in this forum was roller bearers. So I had a metal worker friend fashion us some out of aluminum. They are PRECISELY type high. We locked them up in the chase, still trying to keep the rails as close to type-high as possible as well.
First, we were over-inking like crazy. Then we added tape on the back of the roller bearers to lift them up. This seemed to finally stabilize the situation some what.
Now we are consistently having this “seesawing” issue….
We start a run, and the lower half of the print is inking lightly (consistent pressure everywhere). So we add a little patch of paper or tape on the back of the base, in that area. Slowly (over 10-20 prints) it’ll come up to meet the top half. 10-20 prints later, it is over-inking and the top half is now under-inking. We stop, switch the packing on the base to the top half and the whole thing starts over again.
It seems the area with extra packing changes the way the platen makes contact and is shifting the base, ever so slightly back and forth in the chase. We tried unlocking, locking, planing etc every time. It’s also strange that each change takes at least 10 prints to take effect even though we plane and wipe the plate each time.
I noticed one thing in clean up last night that could be effecting the situation. It seems the entire roller carriage is shifted a bit to the left. The trucks graze the ink disc on the right side, but not on the left side. I am wondering if there is some asymmetry in that shaft that could be causing some cyclical weirdness.
I hope you all have some wisdom! Thanks.
Are the rollers matched to the trucks? Are the trucks metal, rubber-tire, or composite? And are the trucks and rollers true?
DO NOT add anything to the roller bearers; doing so defeats their purpose. As for adding tape to the rails, well, that, too, presents a never-ending guessing game. Either grind or re-build them.
I have to concur with Forme that adding tape or anything to the bearers would defeat their purpose and that the rails should probably be reground if they are very uneven. He is also correct to suggest looking at the trucks and rollers. If one or more of your trucks is worn egg-shaped or is wobbly on the roller core, it can cause inking problems.
The other thing I’d look at is the interaction of your chase, base, platen and press bed. If the base is moving, then something is not flat or tight. I had a Star that used to do just that with wood blocks. It turned out that the chase was sprung and rocking slightly with each impression. Also if one side of the platen is pressing harder than the other, it can cause shifting. Check to see that your impression is even.
Finally, I’d look to see if the platen is shifting slightly left or right (or up or down) as it closes…. or if the roller arms are not moving smoothly. This can indicate worn bearings which will drive you crazy with all sorts of impression/inking problems.
Thanks for the comments.
Yes, rollers and trucks are matched. My trucks are also new, Delrin. We have tried a couple different chases since the first one did look warped. I will examine the platen & roller arm motion some more and report back. Also, will check the pressure, but it seemed pretty even last I checked.
I understand what you are both saying about tape on the bearers. We just about lost our minds when we realized we had to add it. Without tape on the bearers, the type just looks like huge blobs! I mean really over-inking BADLY. Any ideas about how to stop that otherwise? I haven’t locked up a mag plate yet to see the difference (since we are on deadline), but to the eye, the Boxcar base + plate sure looks higher than a mag from Owasso.
Thanks again for the help.
Also, does the fact that the rollers are shifted right suggest a problem that could cause these inking issues? Next time I print, I’ll check if they are uneven as soon as I put them on, or if it shifts during a run.
How much ink are you putting on the ink table? Doesn’t take much.
Are you planing the chase? Is the chase rocking on your imposing surface?
I’ve found that tightening hempel style quoins can make them shift vertically and make the chase rock until they are tapped back into a flat configuration. Furniture can ride up (or down), too. If a chase stubbornly rocks even after checking all the quions and furniture, I’ve been known to tap the chase itself in the corners with a mallet. That will often minimize the rocking. But sometimes you just have to redo the entire lockup.
Also measure the boxcar base and plate combo to determine exactly how high they are.
Not much ink at all, I have used much more in the past on other presses. We even ran a piece of paper through the system to take ink off, just in case.
We have planed again and again. It is not rocking, although our composing surface isn’t totally perfect. We’re using high-speed quoins, the hempel style is asking for trouble!
I might try a mallet (if nothing else but to release frustration!). Also starting a fresh lockup is a great idea. I have tried different chases and moved a couple pieces of furniture around but I’ll start from scratch with a different configuration and see if that helps.
The Boxcar base is so heavy and I don’t have it in the center of the chase right now, I wonder if the weight to one side could be making it unstable? So many variables!
SweetLetterPress,
Hi, my name is Maggie. I just printed my first job on the same model press (C&P 10x15 OS) and found the same uneven results. (boxcar base and polymer plates)
I can place the 120 cards I printed into 4 distinct piles:
1. look just right
2. have a vertical stripe (about 1.5”) through center of card where the ink is too light
3. have a vertical stripe about same size on far right side of card where ink is too heavy
4. have a vertical stripe about the same size through the center of the card where the ink is too heavy
The issue seems cyclical.
Were you able to resolve the issue?
Thank you!!
Maggie
I had similar uneven inking with with my old 8x12 though that problam was due to out of round tires on my Morgan Expansion trucks. But it does make me wonder if the problem might not be that the base and plate are too high. If that were the case the plate would not only get over-inked as you describe but one or more of the rollers might be held back briefly from rolling thereby shifting the distribution of the ink and causing the under-inked area to move on the form.
Whatever the mechanism by which it is happening, the fact that increasing the height of the roller bearers to above type high improves the situation would seem to bear this out, no pun intended. If, as an experiment, you raised the bearers some more I wonder if that wouldn’t solve the problem altogether. That might reveal the culprit or rule one out. As Arie suggested, I’d check the height of the base and plate.
Rich
Front Room Press
Milford, NJ
http://frontroompress.com
http://frontroompress.blogspot.com
It may be possible that you are either locking the furnature in the chase too tightly, making it not lay flat in the chase or not locking it down on a completely flat surface like a slab of marble.
There are so many varibles that make a press print poorly. it is very frustrating if you are also trying to learn, and dont know what it could be. We all have been there.
I do know that uneven rails make a press print terribly, and that i would never buy a press with uneven rails. i know that this is the last thing you want to hear. but maybe some of these people are right and the rails can be releveled? I hope for your sake that they can. That would be where i would start. If you cannot get the rails evened out, it could be used as a diecutter.
Many of these printers say that taping the rails is not good, but they are wrong. as long as it is only a layer of scotch tape or so, and as long as it is not used for runs longer than say 1000, it is actually the very thing needed to get the exact level of the rollers.I wish this wasnt so as well, but I can tell you that polymer plates vary height even on the same diesheet. and taping the rails accounts for this.
This is if you are printing with impression-if you are one of the kissers, you should be able to run tons of ink and this matters far less. It would be very helpful to know which people are on here, because it is a completely different type of printing and many of these posts are confusing when this difference isnt mentioned.
It is also possible that your rollers are way too big. they should be close to the same size of the trucks. I recommend calipers to measure the width of all of your trucks and to measure your rollers to make sure they are all even.
It is also possible that if you are getting 10 prints or so that are good and then it starts to mess up, that there is too little ink on the plate, or that your die is actually too low. strange, but when it is too low, certain spots will actually overink and others will underink.
basically, you just have to troubleshoot, and become familiar with your press. it will take lots and lots of time and patience, but that is what this is all about.
good luck.
Wow! A lot more has gone on here since last I checked. Thank you all for your comments.
We’ve managed to contain the issue somewhat by keeping the ink in the system on the light side, checking the lock up often, and printing smaller sections at a time. This turns one press run into two, but I think saves time and sanity in the end.
It seems certain colors (deep blues) are the most prone to the issue. Would there be any reason for that?
Good luck to all!
SweetLetterPress —
I know it’s been awhile since you posted about this issue, but are you still getting the same uneven results?
Or did you find the culprit(s)?