No 4 Motor Vibrations

Help! – our No 4 sounds like a freight train and can be heard two floors up.

Thinking the sound was possibly coming from the ink drum or chain, I removed the belt that connects the motor to the gear box, but no luck. The motor itself is quite (I disconnected it from the press and turned it on while it sat on the floor) but when attached to the press, it causes vibrations that make the metal cabnit resonate and the floor shake. The motor appears to be connected as per the diagram in the manual and the bolts that hold the motor base onto the underside of the gearbox have rubber washers.

Is anyone familiar with this problem? Would adding rubber to the points of contact where the motor/gearbox assembly attaches to the press frame help?

My suspicion is that the motor itself is to blame. When I’ve put my hand on it while it’s winding down, it feels as if the shaft is acentric – creating a wobble. The motor is a Dayton model 5K460A, 3/4 hp, 1725 rpm. Anyone have the same motor?

9 thoughts on “No 4 Motor Vibrations

  1. Paul Moxon, Moderator - May 24, 2012

    I say this press on May 21. The motor was the loudest motor I’ve ever heard. So as Chris said it will have to be replaced. There were the usual repairs: new form roller clutch pins, springs for the carriage latch spring and front trip wedge, LB-7 copper paper guides and the cylinder needed to be retimed. Other than that it’s a nice press and appears to have seen little use since 1948. It will be a great addition to their studio.

  2. John and Nancy Johnson - April 28, 2012

    Chris, We don’t have any vibration issues with our #4, only a little chain rattle. Maybe you can try mounting the motor back onto the press and disconnecting the chain from the gear box to eliminate the turning of the inking drum. If there is no vibration with the motor driving the gearbox but not the inking drum you would be narrowing down the areas of possible problem. Another thing you might check is the tightness of the chain. A really loose chain might cause some vibrations.

  3. chris_dunnett - April 27, 2012

    John & Nancy,
    Thanks for comments. Do you have an issue with the motor vibrating the press?

  4. John and Nancy Johnson - April 27, 2012

    The pulley you have matches what we have on our #4. Our motor/pulley is set up as yours is – there is a keyway on the motor shaft but not in the pulley, and a hex screw is tightened into the keyway of the motor shaft to hold the pulley in position.

  5. chris_dunnett - April 27, 2012

    On further investigation, the motor shaft has a key slot but the pulley does not. The pulley attaches to the shaft with a hex setscrew that goes into the key slot on the motor shaft to stop it from turning. Looks like the pulley is improvized. Does anyone have a photo of their #4 motor pulley? I’ve attached a photo of ours. I assume Grainer stocks such an item? We have a flat belt.

  6. Eric Holub - April 27, 2012

    A square key is not a lead wedge. It is steel, and meant to fix the pulley to the shaft in alignment, without slippage. It is not meant to give.
    I’ve had worn v-pulleys that cause just such vibrations, but the 4s I’ve seen all had flat belts from motor to gearbox. Still, running a pulley without the key can result in wear and eccentricities that cause vibration.

  7. Paul Moxon, Moderator - April 26, 2012

    Square keys are easy to get and the length can be cut, but you should measure it. I’ve seen motors on No. 4s from various manufacturers. This model was in production for 25 years.

    We’ll discuss a visit via email.

  8. chris_dunnett - April 26, 2012

    Yes this is missing – the soft lead wedge inside the pully that protects the motor from excessive load. Other then it being a square 3/16″, are there any other specs for them? I assume they can be purchased at any hardware store.

    If you can stop by that would be great. We are having an issue with the carriage rollers that I’d appreciate an informed opinion on before adjusting.

  9. Paul Moxon, Moderator - April 26, 2012

    This will be hard to diagnose without seeing it in person. In an email you mentioned the this press (c.1948) had been neglected: “at one point the ink drum/well had caught on fire – leaving lots or caremalized ink in the tray. We also found a family of dead mice up inside the frame.” It could be that there is more ink inhibiting the chain/sprocket or that the gear-box needs more oil.

    You say that the motor is quite on it’s own. The wobble could be caused by the absence of a square key to secures the pulley and the shaft. Are there notches on each part? These should align to fit a 3/16″ square bar. Still, you may need to replace the motor. Contact Grainer or McMasterCarr either should have a replacement.

    My time in NYC is brief, but I could arrange come by before or after workshop at CBA.

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