Roller trucks, free or fixed?
One of my rollers came with the press with trucks missing, I think. Anyway when I had the rollers recovered they replaced the trucks with new plastic ones (turned to the same size as the other roller), than slide on and thus spin freely. The original trucks on the other roller are fixed in place. Does it matter? Would it be better for the trucks to be fixed in place so the roller starts turning before it reaches the type on the form? I haven’t noticed anything grossly wrong with inking but don’t think I’ve had any really small type on the first line anyway, usually a title or image. Thought about putting a little spot of superglue on them, should be enough to keep them fixed but still possible to break the trucks free if needed? Thanks!
Trucks should be “keyed” to the roller so the roller and truck revolve at the same time. In other words, the roller shaft should have a set of divits or “keys” near each end and the trucks should have corresponding slots that slip over those keys.
Michael
Michael is correct. If the trucks aren’t keyed (or secured somehow) to the rollers, then the roller surfaces can slide, to a greater or lesser degree, on the image areas of the form and partially wipe the ink off. This can, and most likely will, be noticeable the print.
If you haven’t noticed anything so far, I’ll bet you have the original roller with the trucks fixed in place, positioned in the press so that it is the last roller to ink the form before the press closes and the print is made. So that roller is compensating for any problems the non-fixed roller might be creating.
As I recall it, all my C&P rollers had the cores crimped in specific places to raise lugs, some as an inward stop for lateral location, others as keys to fit into the truck keyways for rotation.
On other presses I’ve seen pins that run through the center of the core, and these fit into radial slots on their trucks, securing both location and rotation.
Simplest thing I’ve done on featureless Kelsey cores and trucks (meant to be used with Kelsey roller bearers) is to drill and tap the truck for a small set screw.
Thanks! It’s not obvious how exactly the “fixed” trucks are actually attached, maybe just pressed into a differently sized part of the core. I’ll take a closer look and come up with a good way to do it. And/Or try roller bearers maybe. No idea the if these rollers are original to the press (small Star job press) or not, they may be from a tabletop. (Rails are about 13” apart)