Rollers inking unevenly
Hello,
I have a 10x15 C&P Craftsman that I ran my first prints on this weekend. Woo! We had some trouble with the rollers inking evenly so I’m calling out for help.
The rollers and trucks are brand new (on old cores) from Ramco. The trucks are a tiny bit smaller than the rollers.
As you can see in the photo, the top two rollers picked up ink on part of the plate. The lower two hardly even touched the ink plate.
I taped the bed rails because the rollers were inking every surface within the chase. That helped but I know it is not the long term solution. It seems as though the rails next to the ink plate (I can’t find the technical term for these, sorry!) are shorter than the bed rails but if they are raised, the rollers do not pick up ink at all.
I do have four metal trucks that we used to progress with printing using two rollers only and these trucks are a full 2mm smaller in diameter than the new trucks.
Are the trucks too big? Or are the rails incredibly uneven?
If anyone can help me out I would greatly appreciate it!
Thanks,
Janina
unevenink.jpg
Swap the top pair of rollers for the lower pair and try again if the effect stays with the lower pair placed at trhe top then your bearers(trucks) on your rollers are wrong if they ink up when swapped its your bed bearers(rails) that are wrong .
Janina:
On the C&P Craftsman presses the roller support tracks are adjustable, both alongside the bed edge and alongside the ink disk. It may be possible that the roller tracks have been raised beyond where they should be at the lower edge of the ink disk, so that the lower two form rollers aren’t properly picking up the ink. There should be no need to put tape on these rails as they are adjustable.
Take a look at the adjustment mechanism behind the rails and do you adjustment by turning those adjustabel bolts one way or the other.
Why are you not using the original trucks?
DGM
@ Peter - I will try that tonight and bet that will confirm one way or another. I’ll let you know what happens. Thanks!
@jhenry - We did adjust the support tracks but that didn’t help. When we raised them, the top rollers were too high so there was no inking at all. When we lowered them, we still had the same problem with the top two inking up but not the lower two. Which is why we were wondering if the trucks are too big…
@the Arm NYC - I switched to those and they worked fine for doing some first prints and getting the hang of things…but I only have four metal trucks total (this press took a cross country journey in a crate…I got 3 bearings and 4 trucks so I’m guessing the rest are rolling around somewhere on Interstate-90) They are not in very good shape and I can only run two rollers at a time which seems to increase the roller speed quite a bit and I’m guessing this is not good for the rollers?
There is a comment in the manual for this press which talks about special trucks which raise the lower rollers on the downstroke, but put them in normal position for the inking of the form on the upstroke of the roller frame.
This feature is highlighted on p. 17 of the Craftsman Manual:
http://letterpresscommons.com/files/2012/10/auto-platen-presswork.pdf
but I doubt that is the culprit. It just seems unusual that these same two lower rollers are the ones effected by this special mechanism.
It seems like you must have the wrong size trucks or the roller tracks are not set properly.
John Henry
Have you cleaned the rollers thoroughly? The bottom two look in the photo like they are not picking up ink uniformly due to something (oil? condensation?) on the roller surface. But if you’ve swapped the top pair (with trucks) and bottom pair and the problem persists on the new bottom pair there is apparently an adjustment problem.
Bob
I didn’t clean the rollers, I just put them on straight from the box and then removed the paper.
I have another question. How much smaller should the trucks be than the rollers? We measured them both with a caliper and the rollers measure 44 mm and the trucks also measure 44 mm. The trucks should be a bit (how much?) smaller than the rollers, right?
The old metal trucks measure 42 mm which makes sense as to why they would pick up ink on the plate and then ink the entire contents of the chase…
Headed out to swap the rollers to the lower saddle and see what happens. Will report back. Thanks for all of your help already. What a great community! :)
@John Henry - I have not seen that manual but it looks really great. I will print it out and read through.
Janina,
On a separate topic, by the picture it looks like you may have too much ink on the press. I am assuming the color is Pantone yellow or something similar, and that you didn’t put any opaque white in it. It is common for beginners to put on too much ink at first, and it is certainly not an adverse reflection on you.
The people above have given you great advice on possible fixes for your roller problem, and I hope you can fix that soon. When you ink the press up again, try starting by putting on much less ink. Your prints will be much better. If you need to add ink, you of course can.
You could carefully caliper all the trucks and all the rollers, and have a machine shop turn down the diameter of the trucks a millimeter or so smaller than the rollers, but since you have adjustable rails on the press your best bet is to get the rails properly adjusted with the trucks and rollers you have. The ideal combination is for the roller surface to rotate at the same surface speed rate as the truck surface, which means they need to be the same diameter or the truck very slightly smaller — maybe 1/16 inch smaller overall diameter. Using a type-high gauge and a good 2-foot straightedge to span across the bed rails side-to-side, adjust the full length of the rails to type-high on both sides. You can then back them down a very little at a time until you’re inking satisfactorily.
But do clean the rollers thoroughly with roller wash, too.
Bob
If you are running polymer, I would do my best to ensure that the roller trucks are the same size as the rollers.
I use Morgan Expandable Roller Trucks but keep them set to the exact roller diameter, but I’m running a C&P 10 x 15 OS with tired rails.
I would find a decent straightedge and sight across the rails and ink disk at this location to see what the relationship is. I am wondering if the Craftsman presses share the Kluge feature wherein the ink disk can be dropped so as to not flatten the roller if the press is left closed (or for whatever reason Kluge designed the feature).
Our attempts tonight of moving the rollers to the lower saddle produced the same results. I will do some measuring tomorrow and hopefully with all of your great input, I can figure this out.
Thanks so much to all of you!
the suggestion of having a manual is the best as you need to know as much about your machine as possible to get the greatest benefit fron the features it has (adjustable bed bearers (rails to you ) will be an asset where you have out of standard pairing of rollers and roller bearers (trucks to you ) whatever dimensions the rollers have and bearers (trucks) all the set you are using in the press ought to be the same . With no information you may have to raise the bearers throughout the machines bed and inker bearers and measure the max height from the bed they can be set to , then lower the lot to minimum and take that measurement ,this will give you a range within which you can start calculating .
If your bearers on the bed measure type high in the range not fully up or fully set down then you can have roller bearers (trucks) made the same diameter as your rollers regardless of the diameter of the rollers . However if you cant achieve type high with fully raising your adjusters you then have to determine what undercut is required ,if that full height for instance is 20thou short of type high then you will need bearers to be 20thou bigger than your rollers to allow for the difference between the bearer height and type height however it should be noted that you are measuring the full diameter of the roller so the difference you have calculated will be twice so the 20 thou is actually 40 thou on the diameter . If you use thatCalculation principle as a sample and set your rails mid way not fully up or down and then find the difference you will have leeway should the rubber be softer than anticipated or harder .
Hopefully now others will read this and double check i have it right ,not having any measure of your press i can only try to explain but the method works ,you can also carry differing diameter rollers to each other as long as the trucks relate to the under cut for each diameter of roller and as long as you dont have any rider roller touching any pair of odd size rollers ,if all your rollers are exactly the same then they can be spanned with riders as the peripheral lengths are equal but if they are not the same they cant be spanned as the roller surfaces are rotating differently even though they are rolling the same distance down the form they are not rotating at the same rate /length therefore nothing can connect the surfaces .
a big barrel rolled for one yard may make 3/4 of a revolution but a smaller barrel rolled the same distance will make one full revolution put those barrels like wheels on a car and you can roll along all day long without a problem ,one making more turns per yard than the other yet still travelling freely .However if you add a roller between the two and they three touch the rotation will be interrupted because the ratios may not match and a skidding effect can occur .
Excuse the long wind of it ,i should keep a concise explanation of this as it is probably one of the most common question s asked here . This principle works because everything free wheels .
Update: We found the four impression screws on the sides of the bed. We loosened all of them completely which made the rollers move away from the bed and I could fit my roller gauge in without even touching a roller.
After a lot of tinkering and experimenting, we tightened them back up as much as we could and it seemed that only one of them actually tightened. At one point in this process, it seemed like we were getting everything aligned but that quickly ended when we adjusted one of the screws.
Thanks to all of you for your very specific help. My copies of General Printing, LP Printing, and the newly printed Automatic Platen Presswork are getting their use but it’s nothing quite like hearing directly from the experts!
I think we need to spend more time adjusting and we will eventually get everything where it should be. Hopefully!
Taking in to account all of the above, and noting that every configuration comes back to the same end result, could it just possibly be, that there is a fault or mis-configuration with the bottom two return springs, and the rods that they enclose, i. e. split pins missing or dried ink rings, from non use restricting their pressure on return??? Just a simple overlooked idea, possibly!!! Apologies in advance if it is a “Red Herring” Mick.
We got it!! The large hex bolts were the key to adjusting everything. I ran some prints and it runs great. Thank you for all of the help and suggestions.