We have a No 4 (S/N 8655) that seems to take more effort lately to return the carriage to its resting position at the feed table. There is no problem leaving the feed table in trip or in print. Returning to the feed table seems fine in both trip and after printing an image until it gets to the position just before ‘locking’ into the resting position. This happens just after the grippers rise on the return. If I increase the speed at which I return the carriage, it settles into the resting position, but with considerable force and noise. If I return the carriage at a slower speed, I actually use both hands to finish the return. Is this most likely related to the trip-print mechanism or with the gripper mechanism? Any suggestions on how best to diagnose and fix the problem?
John Johnson
Jonathan Jarvis’s photo didn’t attach because it was a tiff. The WordPress plugin only allows jpegs.
photo here shows on a Western press a(a licensed Vandercook copy) the little holders with felt inside that can, if bent /damaged etc stop carriage fully returning to bumper
The diameter of the MR-68 on my No. 4 is the same: 1 5/16″.
I don’t have the oliers or see them in the manual.
Jonathan, I don’t think our press has the oiler area you mention. If it does I certainly have been remiss in putting on oil. I know the carriage is going back to and contacting the bumper springs. Do you happen to have a part number where I could look it up on the diagrams?
Paul, I measured the roller (MR-68) and it is 1 5/16″ in diameter and checked to make certain it spins freely. I also measured the roller on our SP-15 and found it to be a little larger, but it is also a different style of roller. Do you happen to know what the appropriate diameter is for the #4?
John
just a thought-the little brass holders that hold felt to oil the bed where the bearings run can get bent damaged so they stop the carriage going back fully to come up against the bumpers…….
It’s a puzzler, John, but glad it’s fixed in any event. Could it be that the roller (MR-68) on the bottom on the gripper trip lever is worn and/or gummed up and not turning freely?
You’ll find that locking the latch makes for quieter printing, because the grippers are not snapping.
I locked the latch into manual mode and the issue did go away – that was an easy fix. Thanks Eric.
Paul, There was a nice film of oil between the latch and the arm and it moved freely. I thought I was keeping the gripper assembly lubricated – gripper pins, trip bar & fingers as well as the push bar. Am I missing something I need to maintain? Our N0. 4 is the style that has the bicycle chain mechanism attaching the foot pedal to the grippers.
Resistance could be caused by a gummed-up gripper trip latch that interferes with it sliding easily. The mechanism is also found on the No. 3 and early No. 4s both of which do not have pedals—auto grippers are the only means.
Some No. 4s (and all 15-21) have another latch that hooks onto the vertical of the gripper trip latch. The location is shown in the color highlight on the left of the image before.
Eric, I will try setting it to manual operation only and give it a try. Am I correct that all I would need to do is slide the gripper trip latch bar (part MS-127) back and tighten the bolt to hold it in that position preventing the spring from pushing it forward? John
You have grippers set to open automatically. Does this resistance also happen when grippers are set to be operated only by foot pedal?
If there is no problem leaving the feedboard, then it wouldn’t seem to be the carriage latch.