SP-20 Vibrator Roller Not Oscillating

Hi, there! I apologize in advance, as I am likely using incorrect terms. My husband was using the Vandercook SP-20 earlier this week and the top metal roller (I believe called the “vibrator” quit oscillating.) A few years back I had to replace the worm crescent (thankfully learned how from a Paul Moxon workshop!), so I took apart that assembly again today and cleaned it all out, put vasaline on the worm crescent track and put it back together.

When I hold up and hand advance it, it oscillates just fine. There was no damage or wear to the crescent or the points inside the track when I cleaned it. I made sure to adjust the Crescent Holder assembly just so (not too tight, not too loose, backing it up that ¾ of a turn after bringing it down over the crescent shank)

However, there seems to be a lot of play in what I believe is the DR-348 Collar on either end of the mecahnism that holds the vibrator assembly in place. I feel like the vibrator roller and smaller metal roller in front of it are too loose and sitting too low, putting weight and pressure down on the form rollers, and this is possibly causing the oscillating function to get hung up/drag. If the vibrator roller is to the handle side of the press, it will oscillate to the back of the press, but it won’t return to the handle side unless I lift up the vibrator assembly just the right amount. It rattles and is loose, but I cannot adjust the screws any tighter on the sides of the vibrator assembly, and there is wear on the DR-348 collars around there the screws adjust down. Can I shim this? Do I have to get new collars? Is there something else dumb I am missing?

I also tried adjusting the inking drum with the set screws since I know it pushes up on the form rollers. I took out and cleaned gunk out of the set screws, put them back in and leveled the inking, and it is making good contact with the form roller.

I will post pics of the assembly then me holding the assembly up to show how much play there is and the gap occurring between the vibrator shaft near the worm collar and where it connects to the collar holding it to the press.

Thank you so much for any insight you can provide as to whether I am missing some adjustment, piece, or if there is something worn that needs replacing or shimming.

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You could shim the collar. However, I’ve had success in tapping the worm gear down on the shaft and then tapping the collar. It may also help to replace the set screws.

Also, flip the oscillator brackets so the slot of the shaft runs with the lower end closer to the feed board.

To add to Paul’s comments, what is the diameter of your ink rollers?

Thank you, Paul! Appreciate your help. I will stop by today or tomorrow and use your suggestions. I do seem to vaguely recall watching you tap it now in the workshop I took with you up at Firecracker Press in STL.

And, Fritz, I will check when I get in! I did read some articles before posting here about how if it isn’t the vibrator its the roller diameter and about how they can shrink a bit over time. This press is on long-term loan to us and came with the form rollers, and they have been working for the past 7 years so I am hopeful it is just something else I have done (like putting brackets on backwards or not tapping things in hard enough, though I get afraid to manhandle this machine since the SP-20s seem so delicate to me…) I will check the diameter, however, and I do appreciate your question/comment as I get to the bottom of my issue!

The rollers are suspect as well as Paul’s thoughts. I can see the end bevel is wrong as per Vandercook specs, and 7 years use that you know of plus how many before? Rollers are not forever especially in constant use. It is a necessary evil to spend money occasionally to renew rollers to improve quality and reduce make ready time. The ink rollers and rider roller function within a narrow range of tolerances to perform as designed and once rollers especially have too hard a durometer (measure of hardness) or are less than the diameter specified, then that spells trouble.

I will add that carriage misadjustment will affect roller height on print and trip strokes. If correct, it is the same both ways, but proper roller diameter is a prerequisite.

Are the set screws on the vibrator collar proprietary? Do I need to order them from NA if I decide to try replacing them?

I have tried so far tapping, switching the collar the other direction, and switching the collars to the other side of the press. I still have wiggle room on the shaft holding both the vibrator roller and the smaller metal roller. If I tap it over, it’ll do one full oscillation run. Once the vibrator roller returns to the handle-side of the press then back to the far side again, it loosens again and it won’t return to the handle side of the press, just lulls rotating on the far side of the press and I can see the whole mechanism rattling/loose.

1. First image shows one gap where wiggle is happening.

2. Second image on outside, far side of press (opposite of handle-side) where wiggle is also happening. There were two washers on them, one seems damaged/partial as shown in this pic.

3. Third image I took the other washer off, as mentioned in second image, so I can go to the store and get a couple more of these. I am hopeful they will reduce the wiggle enough.

Is it harmful to not have play in these areas? are they supposed to have give? Or is it okay for me tighten them.

I still have play around the vibrator collars, as well, so I will have to figure that out separately. After messing with them I was able to level the vibrator roller, but they won’t stay in place, possibly the damage/wear to the vibrator collars or my own inability/lack of knowledge to be able to get them in just the right spot.

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The images posted in reverse order as listed above, sorry…

And thank y’all again. I am probably just doing something wrong in general.

and I intentionally took the set screw out in that bottom image to see if I could move things, so that’s not missing—just wanted to clarify! I can’t seem to move anything by taking it out, so I will put it back in.

and I intentionally took the set screw out in that bottom image to see if I could move things, so that’s not missing—just wanted to clarify! I can’t seem to move anything by taking it out, so I will put it back in.

I don’t know about this instance, but some Vandercook collars have a specific location, and then the set screw will fit into a shallow locating recess for alignment. Check if the collar has shifted away from a recess.
A common cup-point set screw probably would be better than a pointed set screw.

Okay, went to the hardware store and bought some of those little washers with teeth facing inwards and shimmed the collars on both sides, and it seems to be working! (knock on wood)

Thanks for your comment, Parallel_imp! I thought the indents on the collar were just wear because whenever I tried to tighten them down in those locations again, it just slipped out of place. Perhaps I just had things place wrong. It is working for now with washers shimming it, but I may play with it again next time I clean the worm crescent