The cylinder check spring broke on our No. 4. I got a replacement spring from Fritz and the press is printing again. My question is concerning the position of the cylinder at the feed table. With the cylinder at the feed table, the grippers are at about the 12 o’clock position (just a little before – say 11:59). In both trip and print the cylinder will rotate very easily before you get to the position where you can feel a small resistance which I presume is the complete engaging of the cylinder/form rollers with the rails. This small rotation is only from the 11:59 position to about 12:02. I don’t remember this occurring prior to replacement of the spring. Is there an adjustment that I need to make at this point? This is an older No. 4 – a 1940 version according to Fritz’s record.
Great news. This one was hard to diagnose online. The top of the block should have an oil hole to lubricate the bore that contacts the shoulder of the bolt.
I believe I found the resolution to the problem I was having. I went back to look at what had changed prior to the problem developing. The only thing I changed was replacing the cylinder check spring and cylinder check wedge shoulder bolt. I checked the wedge and found it was locked in the down position. The spring was not pushing it up after the cylinder moved away from the feed board. I loosened the shoulder bolt and freed up the wedge so it moves up and down with the pressure of the spring. The problem has gone away.
I went back through the comments and realized I didn’t respond to one of the items. The carriage does move forward a small amount, but it does not move so far that the rollers lose contact with the ink drum. The form rollers and oscillating roller continue to spin. The carriage has simply moved away from the feed table an inch or so.
I don’t really need to adjust the amount of opening for the grippers, I was just wondering if the pressure applied by the roller at the bottom of the gripper trip lever on the slanted block would be enough to cause the roller to run down the block, which in turn means moving the carriage down the bed a small amount.
Maybe I need to better understand what actually keeps the carriage at the feed table. If I know why it should stay in that position, maybe I can figure out why ours does not stay there. Can anyone offer a primmer on the mechanics of what keeps the carriage at the feed table while raising the grippers and inserting the paper?
To raise the grippers adjust the set screw first, then if that doesn’t make a difference, turn the fulcrum screw to the right 180°.
I looked at the movement on the off side of the press. The only action is the roller at the bottom of the gripper trip lever rolling up onto the tapered block causing the pushrod at the top of the gripper trip lever to be pushed in slightly – not enough to see any lifting of the grippers. Should I adjust either the fulcrum of the trip lever or the set screw at the lower end of the trip lever to lessen the amount of contact the roller has with the tapered block?
I checked how far the carriage moves. With the carriage all the way back to the feed table and touching the bumper spring, I simply let go of the carriage handle. The carriage then, on its own, moves forward down the bed only about 1/2 inch. It is as if the weight of the handle is sufficient to cause the cylinder to rotate a small amount. Tomorrow I will try to get a better look at what is happening on the off side of the press when this happens.
It’s possible that the cylinder is off one tooth off. Even so, at your12:02 the cylinder shouldn’t have advanced far enough to clear the ink drum. Only after it does so will the trip rack and its cam follower run up the trip wedge causing the cylinder to shift into print mode. See my photo showing how far the carriage has moved and the cylinder has rotated before shifting into print.