Form rollers for a SP-15
I’ve been setting the height of my form rollers the last couple days. Couple questions (more to come)…does anyone know of a set of very complete instructions for setting the height of form rollers? I have bits and pieces here and there, but no…..’setting form rollers for dummies’…that kind of thing.
Also, do form rollers become concave? It seems the back roller is getting a good height set on the ends but in the middle it’s still high. Is the solution to recover the roller? (or maybe it’s just me, in doing this it seems more trickier than I thought it’d be) Where can that be done, recovering rollers? NA Graphics?
many thanks,
patrick
The SP-15 manual has two brief and to the point paragraphs of instructions for roller setting. However, that was written in metal type days and the use of photoengravings and electrotypes. Now we have added in the complexities of photopolymer plates and bases, and the shallow relief etch on these plates requires much closer attention both to roller setting and condition of the rollers. One can get by with murder with metal and wood type in terms of inking, but photopolymer requires strict attention to the roller setting to get proper inking.
The roller setting gauge sets the stage for making rollers parallel to the bed of the press, but should not be considered the end all for final setting with photopolymer. The inking of the plate itself will determine if the rollers are set properly, so religious adherance to what width stripe of ink shows up on the gauge is a partial solution. Bases differ in height, there are plate thickness differences, etc.
As Phogan has found out, irregularities in the rollers themselves defeats any consistent roller setting. Rollers do swell on the ends as they age and that signals the time to get them recovered. There is no cure for this problem except recovering. Rollers are not a for ever proposition. They need recovering on a regular basis, and depending on use and roller wash used, rollers may last a year or several years before they show deterioration.
The other annoying variable on SP-15s is the roller bearing block. This is an under engineered device that tends to crap out over time and usually requires new bearing blocks and possibly adjusting stems to solve the problem of the adjusting stems moving on their own even when it seems they are tightened in place. These presses are in the 40 to 50 year old category and parts wear. Fortunately, we can still furnish all these parts.
Fritz