SP-20 Motor Noise, Chain Bounce

Hello –

Paul kindly inspected my press before I purchased it. During his inspection he noted that the motor was loud, but quieted down quickly. Paul suggested checking the motor mounts, but those checked out fine. I’ve been trying to figure out the odd motor noise and today I noticed something. The noise seems to be a direct result of the ink drum chain bouncing about. The chain bounces when the motor is first turned on and settles down within a minute or so. It also bounces when the form, oscillator, and rider rollers are lowered into position and it stops bouncing when the ink system is lifted back off the ink drum. Any ideas or suggestions? Let me know if you need a video for reference. Thank you for your help.

8 thoughts on “SP-20 Motor Noise, Chain Bounce

  1. Lad Boyle - April 8, 2014

    Don’t know much about chains on presses, but know a fair amount about bicycle chains: they wear out and if not changed, they will wear the gears, which you don’t want. So, i suggest that you change the chain. To be sure you get the right size chain – length etc – you should get in touch with Fritz at NA Graphics – he will have the correct chain or tell you where to get one. For what a new chain will cost, why chance getting the wrong chain and create more expensive problems to fix?

    At least my thoughts


  2. maysorum - April 8, 2014

    After some more fiddling I figured out the starting teeth issue. It seems that the ink drum was up too high which would raise the form rollers and make them miss the starting teeth. Is that a correct assumption? Everything seems to be running smoothly and the chain noise is so much better. Thank you for your help. I do think I’ll replace the chain.

  3. maysorum - April 8, 2014

    The springs are clean. After adjusting the motor the noise improved greatly, but there seems to be a little bounce still. With the motor running I depressed the non operator side ink drum plate and the noise stopped completely. So I started to fiddle and noticed that the ink drum wasn’t level. I adjusted the ink drum so that it is now level by adjusting the set screws that allow the drum arms to raise or lower. By doing so, I inadvertently affected the geared form roller so now it is not quite catching the starting teeth. Does this mean that the ink drum is too high now? Oh boy…

  4. Paul Moxon, Moderator - April 8, 2014

    There should be a slight give to the chain. A new one would likely last longer.
    The arm movement may mean that the springs are crudded-up. You should buy and install them in pairs.

  5. maysorum - April 8, 2014

    I adjusted the motor mount this morning, but now I’m wondering if the chain is too tight. I’m guessing there is a perfect balance between overly tight and too slack, correct? Any pointers on how to determine proper tightness?

    Also, what is the better long term solution for the press. Moving the motor or buying a new chain? Or are both perfectly fine solutions?

    Also, I have another related question. The ink drum arm on the non-operator side of the press seems to move slightly as the chain spins. The operator side of the ink drum arm doesn’t move at all. Does this mean I need a new spring? I also made sure that the arms were properly tightened.

    Thank you!

  6. Paul Moxon, Moderator - April 8, 2014

    Yes. Any industrial supply should have a replacement. This may be the way to go if the slack is excessive. (Too often I’m dealing with people not able or willing to spend money on a proper repair that I get caught up in these half-assed roadside solutions.)

    It’s called chain stretch because the holes that contain the chain’s rollers and rivets ream out over time (going from a circle to an oval) and the cumulative effect makes the chain longer in length.

  7. maysorum - April 7, 2014

    Thanks, Paul. What about buying a replacement chain from somewhere like McMaster-Carr?

    Like this:

  8. Paul Moxon, Moderator - April 7, 2014

    The chain has stretched. It becomes loose when the impression cylinder contacts the ink drum arm (raised plate on operator’s side) pushing the ink drum down. You may be able to move the ink motor downward. There are slots in the motor’s base. Access will require removing the far side panel below the bed. Alternatively, you can remove a link in the chain, but this may also require repositioning the motor.

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