Paul – That SP15 I sold to your friends at Old Dominion last year is having a problem with uneven inking = uneven pressure from the main ink drum. My guess is that, since it is spring-loaded, that either the spring has failed/is failing or that there is a build-up of ink and solvent coming between the drum axle and the top point.
I have explained this to Nikki and her school tech guy is going to be looking into it – after he "reads up on it a bit". Well, since I could not find any illustrations or reference to this problem anywhere else, I figured I should come to you for advice to be shared with Nikki and her tech guy.
Do you have an illustration of the end mounts of the main ink drum for the SP15? Have you encountered this problem before yourself? I have had the drum off of a Model 4, but never removed one from an SP15, so I am just guessing at the cause of her problem. But my "guess" is based upon what I consider to be a pretty fair understanding of how Vandercook designed and built these machines.
But this is something I have no encountered before. I will share any info and/or image links you might have with Nikki. She also reports that although their SP20 has the same setup, it has never resulted in any inking problem.
And, if the spring(s) have failed, is a replacement available from Fritz or some other source you are aware of?
Thanks in advance for your insight and assistance… and, btw, I see you have a new edition of the book coming out. Perhaps it's time for me, too to upgrade my own reference library here. I will be in touch.
Hope all is well with you. Still muddling through over here….
Ink drum springs (X-20771) are available from NA Graphics. Using a spring hook tool old springs can be removed and new ones installed without removing the ink drum. However, wait to do so if the drum will be removed.
1) Compare balance of the drum with the press bed using a spirit level. It may be necessary to add a shim, with a hole for the screw, to the drum shaft support, usually on the belt side.
2) Remove the belt. A timing belt can be walked off the pulley while turning the drum in place by hand. Typically, for a V-belt the drum has to be lifted out at an angle. For difficulty with either type of belt, loosen motor-mount bolts on the under side of the motor box and slide motor forward to provide slack.
3) Remove the socket head cap screws on each end of the ink drum shaft, then lift the drum out.
4) Clean and examine the condition of all components and screws as well as the pulley on the motor.
5) Replace the ink drum springs if needed.
6) Place shim in drum shaft support then replace the drum, noting the orientation of the screw holes the shaft. Recheck drum level.