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February 21, 2019, 04:41:41 pm
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B&I Gem Maker making a bad sound

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Author Topic: B&I Gem Maker making a bad sound  (Read 995 times)
Isotelus
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« Reply #30 on: March 18, 2014, 08:10:28 pm »

Yes there is a concentric circle from the flange on the shaft and tends to wear that into the top of the bronze flange. The gray paint fooled me and I thought I was seeing aluminum.

Yes I see the spiral you mentioned must have been from factory assembly, it's not real deep and has not been a problem. I just did not want to add any more from set screw burs most of mine do have that light spiral- should not be a problem.

Is the top of your upper bushing smooth with just a little circular wear? There was grease in the first shot. Dickb thought he saw some chatter marks on it and so did I.

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Bryan
mossagatemac
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« Reply #31 on: March 18, 2014, 08:43:51 pm »

Here are some close ups of the top.  It looks like there is some pitting or something on the top near the center.  It feels pretty smooth and didn't look too bad in person, but it really shows up in the picture (even more than just looking at it in person).


* top_wear_1.jpg (193.41 KB, 980x1306 - viewed 4 times.)

* top_wear_2.jpg (193.23 KB, 980x1306 - viewed 3 times.)
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dickb
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« Reply #32 on: March 18, 2014, 11:03:16 pm »

That surface should be as smooth as the bottom flange. Those cuts in the bearing might be from metal shavings from the spindle flange bearing surface. If the shaft was run without lube for a time then the surfaces may have heated up and galled the spindle flange and embedded metal, Silicone grit, or rock dust into the soft bearing surface. Before tearing it apart, take some emery cloth and smooth both surfaces up then grease the bearings and the flange of the spindle and re assemble the arbor into the pan and give it a try. If it runs quiet for a little while, a bronze washer added to the spindle and greased should get you up and running. Just give it a pump of grease every so often to keep it lubed. There should be very little side to side movement of the shaft and just a slight amount of travel when you push the spindle shaft up from underneath. It should spin in the bearings with no binding or drag when you spin it without the v-belt attached.

Dickb
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Elegance in Jewelry
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minkos61
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« Reply #33 on: March 18, 2014, 11:15:15 pm »

That spiral groove is most likely a grease grove you need that to deliver grease to all of the bushing.
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Ernie
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« Reply #34 on: March 18, 2014, 11:24:29 pm »

Yes it is and I was talking about the top flange of the bearing. That should be smooth.
I would guess that about 4 pumps of the grease gun should fill the arbor and you should see grease at the top and bottom of the arbor. Once it is full then 1 pump  of grease is all that is needed every so often. That depends on how much you use it. The grease pushes the grit from the bearings and lubes the surfaces.

Dickb
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Isotelus
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« Reply #35 on: March 19, 2014, 10:12:09 am »

Yep top bushing starved for lube. Worth a shot to clean it all out re lube and try it again before we have to get in to re bushing it, though that is not all that tough on these. But lets try the simple first.

On one of my rebuilds I found a small mill cut file 4" drawn across a rough flange like this will also help smooth it up. Use great care to keep the flange flat, they often will lap in ok with running. You can color the top of the flange with a black marker then when you draw file you can see the high areas being removed, this will help keep the surface even. Go slow and use care. Wipe up all metal shavings.

With the shaft being only a couple thousandths smaller that the bushing bore it doesn't leave much room for a lube film and if the spiral is supposed to be a grease groove it's not very deep compared to commercial grease groove bearings. I think this is a design or engineering flaw on these- fixable but a nuisance. In the photo's it seems the grease came out mostly the bottom judging by what is on the pulley. One of my six inch machines does this also and I wind up every few months pulling the shaft and putting a finger full of synthetic in the top bush and flange- very seldom will grease flow out the top as much as it does at the bottom and there is no obstruction or dry grease in the bore. It appears this machine does the same.

On two of the other machines I sometimes push up a little on the pulley while the grease gun is on the fitting that helps on a couple of them to get lube out under the top flange. As always wipe up the excess these are great grease slingers.

Does anybody think a bearing with a larger grease groove is a bad idea for the top bushing? I have other antique machinery here with similar shafts that runs with very little attention but all have larger grease grooves than just a spiral scratch.



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Bryan
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« Reply #36 on: March 19, 2014, 07:06:45 pm »

Good call on the grease groove minkos.  Looked too perfect to be from pulling out the shaft.

Anyway, the saga continues.  I lightly smoothed out the top bushing with some emery cloth, cleaned it up, greased everything and reassembled.  Put a few squirts of grease in until it came out the top, spun it by hand a few times, and turned it on.  No strange noises!  So that's good news, but I only had it on for about 20-30 seconds and the top of the shaft became pretty warm after only that amount of time.  Seems like something isn't quite right and is causing some friction.  I don't remember it getting that warm before taking it apart. 

I then started taking it apart again so that I could inspect what was going on, and then I noticed the bottom bushing was starting to come out.  Keep in mind, i can't even turn this thing by hand, but now it's sticking out 1/8th of and inch or more.  Did I not get enough lube on the bottom bushing, so it got spun out when it was running?  What's the recommendation at this point, pound it back in?  Replace it?  other?


* bottom_bushing.jpg (48.54 KB, 490x653 - viewed 3 times.)
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Rockoteer
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« Reply #37 on: March 19, 2014, 07:49:08 pm »

I may have replied but I forgot, especially if it was an hour or more ago.....anyway, I had one just like this but it was a sears.  Didn't really know what it was at the time and sold it way to cheap.
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« Reply #38 on: March 19, 2014, 09:24:05 pm »



Does anybody think a bearing with a larger grease groove is a bad idea for the top bushing? I have other antique machinery here with similar shafts that runs with very little attention but all have larger grease grooves than just a spiral scratch.





In my opinion no it is not a bad Idea to have larger grease groves, at work we do this all the time for bushings in large logging equipment also on small bushings for saw mill rollers and many other things.

 
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Ernie
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« Reply #39 on: March 19, 2014, 09:46:45 pm »

  What's the recommendation at this point, pound it back in?  Replace it?  other?

My recommendation at this point is to replace both . I think what has happened is .
1) it got run dry (no grease) heated up and has shrunk the bushing to close to the shaft and is seizing up.
2) now that has shrunk to the shaft that means the O.D. of the bushing has shrunk which now has made the press fit less and is allowing the lower bushing work its way out.

Why I'm saying this is happening with the bushing is that is how we remove Aluminum/Bronze bushings from blind holes. Heat the bushings up they expand against the housing and when it cools it has shrunk to allow to be pulled out. And I think this is what has happened in your situation .

This is my opinion only and I could be totally off base as I have never worked on a machine like this.

   
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Ernie
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« Reply #40 on: March 19, 2014, 11:05:02 pm »

Well now is the time to replace the bushings if you can find replacements. What happened is the grease gun pressure forced the lower bushing out of the arbor. Now, you can either take a wood block and a hammer and tap the lower bearing back into the arbor, or take the lower bearing out of the arbor, then use a wood dowel that is just a bit smaller that the outside diameter of the bushing and stick it into the arbor and tap the upper bearing out as well. What happened is when the lower bearing came out it tighten up the friction of the spindle and pulley rubbing on the bushing flanges and that is what caused the bushings to heat up. That is probably what made the top bushing score the flange surface. Otherwise just tap the bushing in so it's tight to the arbor and re-install the pulley and try the lap again. You now know what to look for next time you lube the lap and what caused your chatter problem.

It may be difficult to find replacement bushings, but you now know how to get the bushings out of the arbor.

Good luck and have fun.  yes

Dickb
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Isotelus
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« Reply #41 on: March 20, 2014, 08:07:57 am »

The Bushing is an SAE 841 Oilite Bronze  FF 1013 your local bearing distributor can look it up, most don't seem to stock this one. The are made by Isostatic Industries but they only sell through a distributor. Motion Industries locally can get them, their cat # 00003868. A word of advice there are very many similar numbers If after the FF sequence there are more than the 4 numbers 1013 its not the right bushing refer to the measurements i posted earlier.

Again:
Bore  ID .750  OD tube 1" Overall length 1" Flange OD 1.5" Flange lip thickness .125  Never install a longer bush than 1" or you will have no grease space and no easy way to get them out in the future.

Luck is on your side the bottom one slid partly out that is where all the lube accumulates this often makes removal easier.
A 3/8" drive socket extension 5 or 6" long will make a acceptable driver, use the female end with the square socket ( the fat end ) it will slide through the top bushing bore and with finger pressure hold it against the side of the bushing bore slide it down gently and you will feel when it gets to the space the grease occupies between the upper and lower bushing. Keep sliding it down till you feel it contact the top edge of the lower bushing. I use about an 18 OZ brass no mar hammer but any will work. Don't hit real hard just a good solid tap will do.

Whatever point you start at think of it as 12 o'clock on a clock dial then go to 6 o'clock position ( another solid tap ) then go to 3 and 9 o'clock positions tap at each. Keep repeating that untill the bushing is driven all the way out. Then flip machine bowl over and repeat the same operation on the upper bushing. I like to set the machine body up on a couple wood blocks for this. Once the lower bush is out clean out any grease, this will help you see up the bore to find the top bushing edge.

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Bryan
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« Reply #42 on: March 20, 2014, 08:42:51 am »

McMaster Carr carries a very good selection of these types of bushings. Their catalog is online. Look under Bronze flanged sleeve bearings.
Bob
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« Reply #43 on: March 20, 2014, 10:00:59 am »

They ( Mc Master ) do have a good selection, their stock flange OD's only go to 1 1/4" though. Because of this machines steel arbor flange 1 1/2" OD it requires a bush with an 1 1/2 OD flange. I had tried them some years before.

Just watch the measurements folks this one is real easy to get the wrong one there are so many variants.
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Bryan
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« Reply #44 on: March 20, 2014, 05:08:17 pm »

Quote
SAE 841 Oilite Bronze  FF 1013
I didn't see your post before going to the store and picked up two bushings, so hopefully i got the right ones!  Had two in stock that matched the measurements we discussed earlier.  I brought the one that popped out and the shaft with me to make sure I got the right ones.  I'm going to try and remove the top bushing tonight or tomorrow and will let you know how it goes.
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