Hi All,
I just received two newly recovered rubber rollers for a #4, done by Rotadyne. I measured the rollers and one is bigger than the other in diameter by 1/32″. One roller is 2 1/2″ and one is 2 1/2 plus 1/32. I asked the roller company to make them 2.515″ in diameter. Should I send the rollers back to be remade? The difference in diameter- between the two rollers- if I did the math right is .03125. I think that is probably too much. What do you think?
Thanks,
Martha
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Update: we did manage to unstick the screws and adjust the blocks as Eric mentioned above, but we still have uneven inking with the rider rollers, and the form rollers. Should we just keep making small adjustments to the block position? Thanks again for the advice!
We got the rollers back again and they are the same size. Now I need to make a slight adjustment to the blocks to get the upper frame resting perfectly evenly.
Guys,
Thanks for this strain, it helped me solve a quirk on my #4 that has been bugging me for a long time now. My chattering, sticky rollers are now running smoothly thanks to a 2-minute adjustment to the blocks supporting the upper frame.
Go Vanderblog!
I did put the rollers on the #4, and when I inked up, one of the the rider rollers on the top frame wouldn’t distribute the ink.
We decided to send the rollers back and have them grind the larger one down to match the smaller one.
Thanks again for your advice!
Great point Eric. Matching diameter is much more critical on the old style, “bottom frame” form rollers and the removal “top frame” double-rider oscillator prior to the Universal “quick change rollers” and hinged single-rider oscillator.
Martha: please do let us know how this turns out.
I talked to the dealer who sent our rollers to Rotadyne. He doesn’t think there will be a problem, so I am going to go ahead and try them out as they are. He did say if we do have a problem they would grind down the bigger roller for us.
Thanks Eric. Actually yes, before we had the rollers recovered we had the issue with bad contact with the distributor assembly, so I am concerned we will have that problem again if the rollers aren’t equal. I called our roller dealer, they are supposed to call me back later today.
The only problem I see is that when both rollers are set to .918″, the larger roller will be 1/32″ higher at top, and the distributor rollers won’t contact evenly. You may be able to shift the distributor assembly (the upper frame) away from the larger roller to the point that it contacts both forms evenly, but that still may be a problem for the rider roller contacting it.
To shift the position of the upper frame, there are blocks on either side of the carriage, that bear against the ends of the cross-rods of the upper frame. Loosen the screws, shift the blocks, re-tighten the screws, and the rest position of the upper frame can be moved (or skewed) as needed.
On other models such as the Universals and SPs, slightly different roller diameters would probably not make much difference, due to the play built into the positioning of the oscillator. But on these models with the three-roller upper frame, matched rollers are preferable. The question is to what tolerances does Rotadyne guarantee their product? 1/32 is pretty coarse.