Vandercook SP20 Ink Drum Not Spinning

Though the gear and chain are moving, the ink drum on our Vandercook SP20 is not spinning. The drum does move freely when rolled by hand.

I will post to Vanderblog when my account is approved, until then any help is appreciated.

Log in to reply   7 replies so far

Here’s one possibility that I hope receives confirmation from those more in the the know. Perhaps the crescent shaped key inside the drum that tracks the drum core is broken and needs to be replaces?

A crescent is for a worm gear on an oscillator or a ductor roller. It’s probably missing or sheared screws that fasten the sprocket to a hub on the drum.

I managed to get the drum out and discovered that the three screws that attached the ink drum chain sprocket to the drum have sheared off :( Bad news.

image: IMG_3802.JPG


I pulled the SP-20 prints earlier today on this problem and it is the 3 screws/bolts that hold the sprocket to the ink drum—but to shear them off indicates maybe another difficulty. It is a fairly simple assembly and I’d suggest taking it apart and see what’s going on.

Can you spin the ink drum Freely? The Force you need to shear them off is huge. I think it’s warranted to mechanically, not optically clean the Press from top to bottom.

Thanks Fritz and Paul! I’ll update when I get this resolved.

However, if the bolts had worked loose and the drum and sprocket were working against each other for a while, the repeated impact could also have eventually sheared the bolts off — as soon as one failed the stress on the others was increased.