Uni I motor & chain

The motor/chain on my Uni I recently started getting louder. I applied some serious grease and it seemed to quiet a bit, but not much. I also noticed the rollers aren’t distributing ink thoroughly on one end (closest to the chain). I experimented with raising and lowering the roller height and it doesn’t make much difference when there is increased contact between the rollers. Everything appears fine with the form rollers–nothing loose or funky. I also pulled out the panel underneath the feedboard to take a closer look. The noise is louder without the panel, obviously, but it also seems like there is excessive slack to the chain–is this something that could change (after 40 years?!)  and require tightening? And am I correct in understanding that the motor for the Uni I is sealed–unlike a #4–and doesn’t require oiling?

Any suggestions would be greatly appreciated since there are jobs waiting to be printed, but I don’t want to make the situation worse.

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David Black
David Black
13 years ago

Be sure to oil the chain follower/tensioner gears above the motor. They get worn or dry and rattle, thunk or squeal.
You can tension the chain to about 1/2 free play at the center of it’s span. Too much slack and the high angular velocity at motor start up and during operation accelerates wear on the pins very quickly.
Chains only get loose due to wear on the pins (well…rollers and a bit from gear wear too – but mostly the pins)
Anyway, you want absolutely no tension, but no real slack either. about a 1/2 seems to be healthy and deals with any run-out issues between all the gears too.
Maxima chain wax is really nice, a little more beefy than most bicycle waxes, it may compensate for some wear issues too.

Thomas Hardjono
13 years ago

Just a short report-in:

– I did check the oil level on the motor. It was ok and the oil was in fact still very clean. So I closed the nut again (middle hole) and topped-up the oil just a little (from the topmost hole).

– I cleaned the grease off the chain, and applied plenty of bicycle chain lubricant/oil (I went to the local bike shop just for this). This made a noticeable difference. The noise level has gone down.

Thanks again for the question from SpringTide and for the answers from Alex, Eric and Paul.

Thomas Hardjono
13 years ago

Thanks SpringTide. Your email has motivated me to do an oil check on the motor (or even a complete oil change/drain).

Thanks again.

Thomas Hardjono
13 years ago

This question is kind of providential, since my usually-smooth Uni-1 motor suddenly generated some unusual noises last night. Admittedly I have not used it for over a month, and the last time I filled up the oil was over a year ago. I checked the chain and it seems to have reasonable slack. (ps. I too am guilty of putting grease on the chain, but will clean and replace with bicycle chain lube. Thanks Alex for the suggestion).

The extra noise is not loud, but present as background to the motor. However it is more noticeable when I lower-down (engage) the rollers to print. I presume this is because the drum and thus chain/motor is getting some load.

My question: does the room temperature have large impact impact on the motor, the oil in the motor compartment or the chain?

When I started last night the temperature in my garage (where the Uni-1 is located) was about 50 degrees F. After having the heater on for a couple of hours, the temperature was about 65 degrees F.

Any help would be much appreciated.

Paul Moxon, Moderator
13 years ago

Jessica–If you record the sound it can be uploaded. A clacking noise may be the slack chain dragging against the guard. As to the drum

A tumbling or continuous scraping is a
drum bearing like Alex said.

While you’re at it check the roller diameter it should be 3″.

Alex Brooks
13 years ago

The bicycle chain lube is great because it mimics the kerosene/oil mixture. There is a carrier that penetrates and washes out dirt already on the chain, and when the carrier evaporates you’re left with a lubricating wax coating that doesn’t attract or hold dirt. Plus it comes in a nice little applicator bottle. You leave the motor running and apply it to the top of the rotating chain, wiping the bottom of the chain with a rag as it rotates.

Eric Holub
13 years ago

I think Alex has a good point about understanding the drive train. But I’d add that grease is not the right lubricant for a chain. I might use gear oil because of its clinging properties, but a mixture of oil and kerosene is what most older press manuals recommend for similar delivery chains. The point is that the lubricant needs to penetrate all the parts of the chain, and grease does not do that, plus it will probably attract, and hold, abrasive crap out of the shop environment.

Alex Brooks
13 years ago

You are working with an incomplete understanding of how your motor drive is working. The motor is sealed but the reduction gear attached to it is not – it needs to be filled with oil – there will be various screws, and depending on the orientation of the motor one screw will be a fill screw and another will be a level screw. You put oil into the fill hole until it comes out of the oil level hole. The level screw was probably at one time covered in red paint.

Your chain is supposed to have some slack, and too slack is preferable to too tight. You can tighten it, but probably shouldn’t. It shouldn’t make much noise. I would use a bicycle chain type wax lubricant instead of grease, but it probably doesn’t matter.

If I had to guess I’d say it’s more likely that the problem is with the bearing in your ink drum, but that’s a guess. If you need to print asap, I’d suggest hiring a qualified repair person.

Good luck!
-Alex Brooks

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