Clunking Sound on a production press- C&P New Style motorized 10x15 Platen Press

Hi all, I am working in a print shop short term this summer and the regular printer and I are trying to problem solve a concerning noise on the C&P. This printer has been printing on this machine for 7 years and has an experiential knowledge of what is normal for it. This press has been in regular weekly use for at least 15 years. The majority of production for this shop happens on this press.

The press is making a loud clunking sound on impression. This only happens when we register high in the press and only when in print/ on impression. We sometimes have to register this way when we are printing cards with a double bleed. We’ve tried adding softer packing, adding packing behind the base instead of the platen, and lowering the platen. Last week, after lowering the platen, the sound did abate for a time, but not through an entire run of 250 cards. The sound has been happening intermittently for 4 years, and only when we register high in the press. We oiled places where we saw metal on metal contact, right above where the treadle would be and where we heard the sound mostly loudly coming from.

We looked at some other threads where people were suggesting to wiggle the platen to see if there is any play and unfortunately there was definitely some wiggle on ours. I’m attaching a link to a video of this sound in action and would appreciate any suggestions on how to resolve it.

Log in to reply   10 replies so far

I would suggest looking at the platen closing cam wheel inside the right side main drive gear. This is the item that must be oiled daily through the hole in the gear (you will be able to see the cam through the hole with the hole at roughly 2 o’clock). Alternately check that the locking frame cam underneath the feed board on the left side does not have any flat spots in it.


You shouldn’t have a form much above the middle of the platen; this often causes the rocker lock to jump out of engagement, particularly on old presses that have wear in the locking mechanism and the parts may have become rounded. Observation of these parts while the press is making an impression will reveal that the rocker lock is jumping slightly. The ultimate cure is never to lock-up a form so high (they tell you this when you’re a young squirt.)
Usually, you have added stuff under the packing to make the form print; remove this. Then, take a rag and some type wash and clean off the oil from all parts of the working mechanism, platen, lock, etc. Now take some powdered resin (or rosin) and rub it onto all faces on either side; this will prevent the “jump” and result in a solid impression.
WHY you must take out that extra impression material: if you leave it in, you will SMASH your type form, since you’re no longer losing impression strength due to “lock jump.”
Don’t put a form too high on the platen! You’ll wear the old girl out, and may eventually break something. Your press will thank for your consideration by giving you many more years of trouble-free operation.
Remember — Just Keep Printing!

Frank is right about high forms and the platen lock, though I am confused by the resin part.
Today’s typical Photopolymer-on-Boxcar work environment, unless one uses the smallest base possible for the job, creates problems outside established methods, like working without grippers, placing forms off-center and the quoins on the guide edges not the trailing edges.
One possibility for this problem would be to place a balancing element at the bottom of the form, below the sheet, but that’s a very different form lockup.

The powdered resin causes the lock elements to stick together and not jump out when the mechanism hits.
One other cause (on old abused presses) is a weak or broken platen lock spring, but don’t look for that until you track down the other things these old girls might be doing.
Just Keep Printing!

OK, I can see that. The old Challenge-Gordon press I learned on (the previous owner Adrian Wilson described it as wobbly) got to a point that the platen lock was sliding into place inconsistently despite lubrication. I took it apart and found that the platen rocker had been re-timed; a hole had been drilled, off by one tooth, and a pin inserted. Then restored to original timing, on impression, the platen lock slammed in, but was less erratic. Most work shifted to a newer 10x15 C&P NS, and when I added a brake and a rider roller to that, things got easier. Then came the photopolymer adjustment, which would have been impossible on the Challenge-Gordon.

This is what the cam on the left hand side looks like after cleaning it. I’m not sure if that dark area is normal or if that is damage from the times the press has made this sound. Something I noticed is that the smaller rolling piece makes contact all along that tract until it gets to that divet where the dark spot is. Once it is in that position the smaller piece can spin freely and doesn’t make contact with the cam. Again I don’t know if this is normal?

image: candpcam.jpeg


It’s normal for the follower to be clear of the cam when on impression; it is, in fact, desirable. A very small flat spot on the cam follower, if the follower keeps turning, is of little account. Should the follower have a really bad flat spot and slide, then it probably ought to be replaced, since it’s wearing the cam.
Just Keep Printing!

Thank you Frank! That’s good news!

So we are still wondering, what is the metal on metal clunking sound we hear- any risk of it causing the press to seize up?

Could it be the rocker lock jumping out of engagement?

Check the cam follower inside the large bull gear on the right side (opposite flywheel) or the press. You’ll need to turn the flywheel to align the cam follower with the hole on the outside of the gear. This is what Mike was referring to in his earlier comment. You can flood that cam follower with oil in its oil hole and make sure it’s turning smoothly.