Setting stripe ink drum to form on SP-15. How thick a stripe? And, any easy way to adjust (besides raising and lowering the drum/motor cradle (?) stop foot? It’s not an easy adjustment… loosening two bolts while pressing down on drum, micro-adjusting, then tightening (only to see I went too far). Better solution?
I forgot the mention that I check the bed with a spirit level and use the reading to balance the ink drum.
The way I approach it is set the drum a few thousandths above form height, absolutely parallel to the bed. A machinist’s surface gauge with dial indicator works well to find that point, but you can also just use a straight edge on top of a form (over a sheet of thin stock for the rise needed), slid over to the drum.
(Grendl, I can loan you a surface gauge if you want to try that.)
In the manuals Vandercook specified that the width of the ink strike on the roller setting gauge should be between 1⁄16″ and 3⁄32″ for metal types and photoengravings.
When printing photopolymer plates, the ink strike should be slightly narrower because of the shallow plate relief and high base. Read Gerald Lange’s Printing Digital Type on the Hand-Operated Flatbed Cylinder Press. And of course the strike should be wider for larger surface areas (linoleum, wood type, etc).
Before adjusting the (presumedly) factory setting for the ink drum, confirm that the diameter of the form roller is at or near 2.5″. Less ink drum adjustment can be done for the SP15 than for the SP20. I’ve had the best luck by simply adding shims inside the drum cradle.