C&P - Proper Rocker Arm & Cam roller action

Short version/possibly stupid question about a New Style 10x15 C&P:
Is there a point in the press cycle when the rocker-arm and cam roller purposely pause, or is this an issue with my press? It starts when the press is fully open, and the cam roller just seems to slide, not turn, for a moment until the rollers would be about 1/3 of the way up the bed.

And for a bit of detail:
I recently got my hands on this press, which had been sitting in a (very dusty) warehouse. The former owner told me he had taken it somewhat apart to transport at one point and I’ve already discovered some questionable re-assembly (like a backwards pinion gear, which I assume is why there’s two broken teeth in said gear - working on getting it replaced), so something being incorrectly attached or out of alignment is not out of the question here.

I’ve spent a good chunk of time cleaning, oiling, cleaning the oil holes, and oiling a lot more until it’s turning over pretty well, except for the moment described above, where it loses all momentum. It was previously grinding and sticking a bit at various points in the cycle, but a heavier weight oil finally flushed out a ton of grit. There’s no motor or treadle for now, rollers and ink plate are off while I troubleshoot—I’m just slowly turning by hand until I’m sure it’s in good shape. I’ve wiped out and examined the path in the large gear cam, oiled the cam roller. My gut says the rocker arm is supposed to come up a little farther than it does at it’s apex - see the picture below.

So before I start taking bits off the press - what’s the correct range of motion there?

Thanks for your wisdom,

image: rockerarm.jpg


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I am surprised non one else has commented on this yet. Having taken two C&Ps apart and reassembled, I have a few comments. If the flywheel is turned counterclockwise, top going away from you if you are in front, the pause is part of the normal action, designed to give you more time to take out paper and insert a new sheet. If it is stopping or slowing considerably, something else is wrong.

1. Usually the pinion gear and the large drive gear have a noticeable groove or notch hammered into them so they are aligned properly. If they are off one or two teeth it may effect the rotation and pause.

2. The path inside the large gear should not be oiled or greased. The gear cog (in your photo) on the inside has an oil hole that should be oiled so it turns free with every revolution. Also make sure that nut stays tight. Some have a tendency to get loose and even fall off. Gulp!

3. One place to make sure to oil is at the drive shaft bearings on each side, one near the hub on the flywheel side and one at the hub on the pinion gear side. If these have been neglected, there can be a lot of wear and grinding going on.

That’s it for starters.

Thanks for the pointers, Mike.
I assumed a pause was natural, but the sliding moment gave me… pause.

1. Didn’t notice a groove on the gears but will double check on that. That would make a lot of sense.

2. Right, I wiped out the path and oiled the small holes on the little cam roller piece. Perhaps I was overly enthusiastic with my application of oil there, so I’ll wipe the path down again. But that nut is definitely going nowhere!

3. I think those were the final spots that were holding a lot of grit.

Thanks again!

Keeping the “raceway” clean is a good thing. Keeping it oiled is also a good thing.
There is a point that the roller doesn’t have pressure on it and may not turn. This is normal. This also a good time to have oil in the race. Always take note of the roller orientation if you do disassemble. It is really important to put it together the same way.
The nut may not clear the frame, as it does not need to.
If your press’ pinion, key is “broached” straight then it does not really matter which way it goes on. If you need a tapered key then it does.

That’s a great explanation — should have realized that at that moment the track is vertical and not putting pressure on the roller. Thanks!

The pinion is stamped “OUTSIDE” on one side (a pretty good hint), and the key is very slightly tapered. Sadly the gear has some stress fractures around the keyway from the key being forced in the wrong way.

The pinion could probably be repaired if replacing is a problem.

The teeth are pretty chewed up and a couple are broken, so I don’t think it can be repaired. But I’m adding a picture of it - if you think it’s salvageable, that’s excellent news.

Replacing it might be a fiasco. A shop just quoted me nearly $700 to make a new one… I about died.

image: IMG_3162.JPG


You may want to check http://www.rushgears.com/ for a quote and allow them the maximum time and not overnight. It will still be a shock. They have made some beautiful brass gears for me that go on Vandercooks that are not stock gears.

This is a great resource, thank you.

Wow! that gear has met a violent end. how is the main gear? It should have fared better. Most of the “give” would have gone into the pinion, crank shaft, and frame/bearings. I would look for a bent shaft though.
The gear you show is for a hand fed press so it does not have the cam cluster gear. let me look into this.

need a gear? email me, got a NS that we’re going to be sending for scrap very soon. It’s a lovely press, but no one in Winnipeg has room for it… galenasmart (at) gmail.com

eric: Right?? I’m wondering if, in addition to being on backwards, it got dropped or someone mangled it during removal. Took the big guard off and the main gear is in shockingly good shape, considering. Shaft looks good—it’s the U bend style. Other than the pinion, discarded feed boards (not following the logic there, but there was at least an attempt at a plywood replacement), and a lot of sad chipped paint, she’s in decent shape.

galena: thanks, I’ll be in touch!

Resuscitating this thread for unresolved stalling.

Having replaced the pinion gear (a million thanks to those who offered up spares), I’m still getting resistance that completely kills the momentum. As much as I’d love some super jacked treadle legs, it’s probably pretty bad for the press.

I’m 95% sure it’s rocker arm & cam roller related. There’s a moment when the cam roller is clearly under pressure and skidding along the path when it should be rolling, and that’s causing a creaking noise, and vibration in the platen. So obviously I’d love to take it apart and troubleshoot.

HOWEVER. As you can see in the picture on my original post, the rocker arm doesn’t clear the frame and I can’t remove that nut to remove the cam roller. Any advice on next steps? At this point do I suck it up and remove the platen & rocker boxes and lift out the rocker?

does the hole in the main gear look big enough to drive the roller pin out through it? if so,
A) you could incrementally loosen the nut and drive the pin out.
B) with a cherry picker or very careful help you can,,,,,, lift out the rocker with the pin on it. it must be done VERY carefully. there is a LOT of weight involved and the pin can be bent easily. multiple people watching different aspects of the lift, really helps. rotating the main gear during the lift, is usually needed. the rocker will need to clear the frame before the pin can clear the main gear. this is pretty involved stuff. you sure you need to go this deep?
I would look for the rocker arm timing up to the frame. with a wreck like this press had, it is possible the rocker is out of time with the arm. If the arm if coming up to soon and closing too hard, it will cause the press to “Bog down” or even stop.

I ended up taking off the rocker boxes for a thorough wipe down and direct oiling (and to make sure they were on the correct sides), loosened bolts throughout the frame, swore a bunch, drank some whiskey, and retightened bolts. One of those things did the trick and she’s finally winding down naturally instead of stalling at the same point of the cycle.

Thanks for the reality check. I’ll save the all hands on deck engine hoist party for another time/hopefully never.

alright then. some sort of “reverse alignment” happened. nice!

Byrne, It was the Whiskey, of course