Heidelberg KSD cylinder knocking/banging

Hi there, hopefully there is someone here that can offer words of wisdom on a problem.

I have been volunteering for around a year at MOTAT in New Zealand. MOTAT is a science and technology museum (Museum of Transport and Technology). Mainly I have been learning to use a Heidelberg platen as many of the other volunteers are retired printers with many decades of experience in the printing industry.

There is a Heidelberg cylinder there as well, serial number: KSD349183. The machine has a loud knocking sound associated with it when the bed is fully in the machine at the point of reversing. I have attached some YouTube videos to help explain:


Here’s some other points that may help with the diagnosis:
- The machine has always done this since coming to the museum and doesn’t seem to have gotten worse or improved.
- It does not happen when the machine is moved forward slowly, only under speed. The machine is only operated at it’s slowest speed.
- The machine was apparently used for die cutting before coming to the museum and may at one point had a lot of paper drop into it, but subsequently removed.
- Some of the retired printers have said they have seen other cylinders make this sound, making me thing it’s not an isolated problem.

I would love to hear from anyone that has suggestions. As they say, noise means wear and I hate to think of this machine slowly being damaged.


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hi i have seen a machine with louder sound almost bounce due to pieces of paper and oil grease ink whatever compressed in the tooth rack that needs to be very clean and lubricated.
especially when die cutting usually very thick stock that tends to fall in between the teeth that leads to worn out parts if not removed.


If you have compressed air in your shop, get in there while the press is off and spray anything you can out of that gear rack?

I ran Heidelberg cylinders for many years and I used to have a long 5mm. steel rod sharpend to a point and bent at a right angle to clean out the gears and the gear wheel

Without being there, the racks and bull gear sound pretty clean. That noise is happening during the transition from forward to back. I would put the bed in different positions and shove it forward and back. you also want to try to “Twist” it as it lays there. if the side gibs are loose, could easily be the noise.
The idea is to try to find where the “play” is and then figger out what needs to be done to fix it. Shine a light down into the main gear box and watch the crankshaft turn. make sure neither of the crank main bearing towers are cracked( you will see a cracked one move), and the crank end of the connecting rod are tight.
I think though, you will find this noise up in the bed area. it sounds loose, either forward and back, side to side, or both.