Taping the Rails
Hello! I am unsure to post this in troubleshooting or in the beginners category. But I believe most of this stems from being a beginner, so I will put it here.
I have owned a 8x12 C&P for about a year, but have not had time to work with it often. I am starting to print on it and am noticing an uneven impression. With my chase locked in it will only print the bottom of the image. I believe this wasn’t an issue for the previous owner because it was used exclusively for business cards. I’m using nearly the full area of the chase.
2 out of 3 rollers were purchased new when I was given the press, and the trucks seem to be newer as well.The chase is lying flat against the back. This leads me to think (based on other posts here) that the rails are worn down. (Also makes sense because the previous owner used the press a great deal)
However I can’t find images or instructions about taping the rails. I’ve only heard it mentioned and I don’t quite get it. Is there any resource that shows how to do this?
I’m nervous about damaging anything by messing up roller height, but I really don’t want to be so intimidating I don’t use the press!
Allie
You are in the right place.
First you have to think like the press and not guess. When the press was built the rails were new and the rollers were at .918”. The platen was adjusted to be parallel to the bed and was at .968”. Over the years the rails likely have become worn and someone may have messed with the platen screws
(really bolts). You have to understand how these parts work and get the press back to like-new as you can.
First get John Falstrom’s roller and platen adjusting gauge. Pretty cheap. See yellow pages. He is in Lyme Connecticut.
Don’t guess that you need to tape the rails. Make some measurements and know what you are doing. You may indeed need to tape the rails, but know what you are doing and why first.
Keep in touch if you wish and I can walk you through the process. Pretty simple.
As you describe the symptom, it sounds more like a platen adjustment and packing problem.
Get some ink on your shirt.
Inky
I agree with what Inky said, and that is the best solution for your situation..
If I had the press inked up and had to get a job out, and encountered your problem, the first thing I would do is look at the form in the press (meaning the type, woodcut, photopolymer, etc. which you are trying to print from). If only the bottom of the form has ink on it, then it could be mainly a roller and rail related problem. If the entire form has ink on it, then it is most likely a packing and platen adjustment problem.
I’m going to guess that in your case the entire form does have ink on it. In that case the packing and platen need to be adjusted.
Probably everything needs to be adjusted to obtain the best results and minimize possible damage to the press. Yes, get John Falstrom’s gauge.
One other thing, you said you are going to use nearly the full area of the chase. If you are going to try to print image area in nearly the full area, that is too much for that press. As a rule of thumb, if you take all of the actual printing area where you are transferring ink, and squeeze it up together into one solid area, it shouldn’t be more than 1/4 to 1/3 of the area of the chase..
The first place I’d start - as the others allude to - is making sure the bed is level.
So:
1. If your rollers are successfully inking up all the type then it’s probably not a rail problem.
2. If only part of the type is getting inked then maybe it’s a rail or roller problem.
Of it’s it’s (1), and as in your case it’s inking the bottom of the form there’s a good chance the issue is to do with bed levelling or you have too much packing. (As a rough rule, ON A CLAMSHELL PLATEN, if only the bottom of a form is printing then it could be too much packing and if only the top of the form is printing there’s not enough packing).
Occams razor:
If you’ve just bought a press and moved it (and you haven’t dropped it) it’s possible that the bed has moved. Sometimes people (like me) take the bed off the press to reduce the weight and centre of gravity for transport. The adjuster nuts could get moved. You could put the bed back on upside down. You might not tighten the bed down again. Or, the bed could just have moved because the nuts have never been tightened.
If you’ve replaced the packing then I’d be looking at that first. I know on one of my small hand pressed it was adjusted for not very much packing. I went with whatever the documentation said (like 8 sheets of newsprint and some card) and it was way off.
If (2) - get one of those roller gauges. But also swap your rollers into different positions, just for laughs.
Thank you so much for all the help. I am going to get the suggested gauge and measure everything before I mess with anything, for sure!
The press was moved from New Jersey to Ohio and was pretty much full disassembled so I imagine that the platen being off is likely.
Why do people have to write an essay on a simple problem?If you are printing too heavy at the bottom then you have too much packing on or the impression bolts need adjusting.
Lockup up a large piece of type such as a W or M in 72pt in each corner of your chase take a print and adjust the bolts so you have a solid print but not deep impression into your paper .
As stated you cannot get a decent print if you fill the whole chase up, 1. because you don’t get even pressure and 2. there is less ink on the rollers at the sides.
Read Elementary Platen Presswork by Ralph Polk, a teacher of platen printing in the 1930s.