riding the rails

So, I print on an 8x12 C&P, most often using metal and wood type, but occasionally using polymer adhered to a metal base. My problem is this: when I’m printing with type, the roller height is fine, regardless of the wear to the rails, but when I try to use a base, the rollers ink the whole thing. I’m sure this is because the wear of the rails corresponds at least a bit to the wear of my type (or at least has no extreme effect), but the base is actually more to real type height and my rails have worn a great deal.

Currently, I’m lessening this problem by taping the rails when I use the base with polymer and taking the tape off when I use type, but this is both costly and not remotely time effective. Does anyone have any suggestions for a printer who wants to use both type and polymer with a base and somehow easily be able to adjust the ride of my rollers on the rails?

On a different note, I’ve been printing lately with silver ink over an opaque white, but still not getting the results I want. I’ve seen some beautiful, near-reflective silver used by printers like Bruce Licher and wonder if anyone knows what kind of metallic inks can produce this impressive sheen.

Thanks to all in advance,
Emily

Log in to reply   5 replies so far

If you have room in your chase you could lock up a couple of 18 or 24 point rules on the left and right side of the chase, this should keep the rollers at type high, but it sounds like the base might be too high. Good Luck Dick G.

I suspect your trouble is that your roller trucks are not the same diameter as your rollers. Type is more forgiving of this than PP. You should measure the rail height from the bed — use a piece of type and a straight edge laid across from one rail to the other. The face of the type should just touch the straightedge. If the rails are low that will cause the trouble. If the rollers are larger in diameter than the trucks that will cause the trouble. If the PP base plus the PP plate is over type high that will cause the trouble. You should measure all and get as many as possible within spec to solve your problem. Too many unknown variables to guess at.

Bob

Roller settings have been argued repeatedly here, with much contradictory advise given. I agree with Ad Lib that truck diameter is a critical factor. The fact is, photopolymer wants a lighter roller setting than do metal forms, and it doesn’t need a different truck diameter. If you can’t figure out how to alter track height consistantly when switching, then form height is your other workaround: run the photopolymer slightly lower by using a thinner plate or a lower base, or put a sheet of paper as an underlay under the metal form to raise it (which introduces other problems if not done carefully). Personally, I run the photopolymer low by one or two thousandths.

Thanks to all for the advice. Pretty sure my trucks are correct, as I only recently got new rollers with trucks alongside from NA Graphics. Think I may try having my base shaved down just a bit to fit correctly with the wear to my rails. Great idea parallel imp, I’ll be able to avoid taking all that tape on and off of my rails, and the switch between type and polymer may go a bit smoother.

Emily

Using a slightly thinner plate would be far preferable to altering a base (and compromising its accuracy). I use 145-thickness plates on base material intended for 152-thickness plates, no alterations needed (and easily underlaid to get back to .918 when needed).
Manufacturers make plates in many different thicknesses, but most processors only offer a few choices.