Tuesday, July 28, 2015

Servicing a Cavallin Rolling Mill.

 

 

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Iffy

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Something was making my roller difficult to turn.

The handle wouldn't fall down if you let it go.

It was as if a bush was binding, so I decided to service it.

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This roller has a planetary gear system that gives a four 4:1 ratio.

In other words, you turn the handle four times and the roller turns once.

After I took the handle off the box slips off quite easily.

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This is what it looks like in situ.

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It was the first thing I took apart.

Three circlips hold the planetary gears in place.

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Definite wear against the shaft holder.

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And wear on the gear sides.

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Here was the problem.

I have no idea why the shafts worked themselves loose.

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Two had moved forward and were rubbing against the box cover.

Also the gear was binding at the discoloured area.

So I used a brass mallet and tapped them back down flush with the back and then the planetary gears worked smoothly again.

If it happens again I'll tack weld them from the back.

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Once that problem was solved I took the rest of the roller apart.

First I screwed out the height adjustment gears after I took the plastic gauge thingi's off. The things with the numbers on top.

( I make these names up because I don't know what they are called, but you get the drift. )

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Here's a side view.

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Now to remove the rollers.

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There are two steel  pressure blocks that have to be lifted up and removed.

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This picture was from an earlier time I serviced the rollers.

One has to use a small flywheel pullet to remove the gears but it is not actually necessary to remove them whilst the rollers are still in the frame.

The rollers can actually be removed from the frame and then the gears can be removed afterwards.

Much easier.

I have no idea why the gears are so tight on the shaft--maybe it's only my roller.

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Anyway, the next step is to raise the top roller as high as you can and then use some cable ties to hold it there.

Then the springs and bushing covers can be removed.

Once they are removed, the bottom roller can be slipped out of the frame and then the top roller can also be removed.

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Once everything is removed the frame can be cleaned and repainted.

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And the various components can be cleaned in turpentine.

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I mounted the rollers in my baby lathe and sanded them down with 1200 grit wet or dry sand paper.

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I just use a buff stick to clean and smooth the square grooves.

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I sanded the bronze bushes down and polished them on my polishing machine.

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The painted frame, handle and box.

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The entire roller cleaned and ready for re assembly.

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The drive gears are marked E and EE to make certain that they go back in the correct order.

As in, the two E gears go together and the EE gears are also partners

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First the bushes are fitted back to the frame.

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Then the top roller is slipped into the frame and hung in place with some cable ties.

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Then the bottom rolled is slipped into the frame.

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Grease is liberally applied to all bearing surfaces and the two covers and the springs are fitted.

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Then the cable ties are cut and the top roller is lowered onto the covers and springs.

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The steel pressure blocks are greased.

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The bronze part is also greased.

The little lug goes into the hole in the top of the bronze bush.

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Like this.

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Now the adjustment handles are screwed in until they touch the steel pressure blocks.

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The gearbox is re assembled with lots of grease.

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The gears are tapped back onto the shaft keeping in mind E goes with E.

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Finished.

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Aligning the roller.

The center handle is removed and each roller is turned independently down until there is the thinnest strip of light showing through the top and bottom roller surfaces.

Once the light is parallel the rollers are aligned.

The center adjusting handle is then replaced.

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