Re: vandercook / heavy stock
I feel like I would need to look at your setup to understand the trouble you've been having. I thought maybe I'd catch on from the posts, but I'm still unsure why you have trouble feeding.
We've routinely used 300 lb Waterford, 250 lb Bockingford, and Lettra Duplex which is essentially 220#, all on the Vandercook. I don't know of anything special you would need to do to feed it, unless, as someone brought up, your paper is small and it tries to stick straight up. Even then, it should still work ok, except you'll need to trim of the end of the paper to clean up the bit of ink it picks up when the end of the paper slaps the plate as it rolls past due to its stiffness.
One thing I can offer based on my experience with my own press is that there was a time when I was dealing with a bearing that was worn down on the opposite side from the press operator. Because of this, the grippers were not rising to their full height. I had to build up the track a little - maybe it was with some thin steel rule left over from plate material? Something. I rigged it. Also, there was a spring behind the ramp that had broken. I tucked a piece of furniture behind the ramp (it seemed just the right size) to offer better resistance. Then the grippers worked fine. My sense was that they were designed to rise higher in the first place, but due to wear, and the spring breaking, were not rising very much anymore at all. Mine is a very early model 4 - about 75 years old now I believe.
I don't know if that helps. If you think that may be your problem, here's what I would suggest based on our press's layout: Have someone slowly wheel the carriage out and back for you as you carefully watch how the mechanics work on the opposite side. Carefully manipulate the parts and movements as needed to understand their functions. When you understand the mechanics of the gripper system (it's a lever with a bearing on the bottom that travels up an inclined plane) you may be able to see what the problem is and why the grippers aren't raising sufficiently. On mine, I'm able to manipulate the lever with my hands and raise the grippers manually which is how I figured out how to get around the problem.
(It would sure be nice to restore it some time so that the bearings, ramp and spring are the correct specifications again! I hope I didn't just make everyone groan in frustration at the knowledge of my little rigging effort. )