There you go Sam, proving the point that others have made. If an oxymoron is something that means the opposite of what it "sounds like", then what do you call it when something sounds exactly like you think it would, given what it is?

Rusty,
Try what EP wrote about the ignore list. It works. I'm going to start doing that will all who insist on writing acidic words towards others on a regular basis and have taken the fun out of sharing with others and asking questions. I have noticed that questions have slowed down on the forum, probably because people don't like to be belittled just because they want to learn. It may cost me some valuable information, but there is always a price to pay for anything we do and I have determined for me, it is worth it.

Regards,
John J

Hey Pete, the "ignore" feature works great! It's like they're not even here, almost. I guess some of the threads may get a little confusing, but as JohnJ says, you pay for everything, one way or another.

quote:

Originally posted by electricpete:

There is one. Click on "Sam Pickens" (or whoever it is that you want to ignore). Then select "Add Sam Pickens to my ignore list". Then all of Sam Pickens' posts look like this:

quote:

Ignored post by Samuel Pickens posted 26 November 2009 04:19 PM Show Post

If you click "Show Post", you can view the post. Then you can click "Hide Post" to get rid of it again.

Excellent.

Thanks, Pete!

You come out and outright and with malice attack me: no where once did I do that.

I have talked and/or argued maybe or put forth my opinion on topics - do I have to agree and have no right to voice my opinion on subject matter. It's OK to attack me, but if I defend myself; then.

I've seen such on an elementary playground and in some inner circles in a very, very few plants that have an unspoken good ole boy club. But in an acedemic forum or one where people are trying to help and promote and build-up - this is not the place. If you want to complain or whin, contact the person directly and resolve any misunderstandings or agree not to agree. Regardless, we all have to give account for every word, deed and thought

quote:

Originally posted by Jonesy:
In another recent discussion one of the posts mentioned stages of failure 1 to 4.

I have heard of these "stages" but have never really gotten familiar with.

Could some of you explain the stages? like amplitudes etc one would expect to see at say stage 1 and how long before stages 2 and 3 finally 4 are reached. Any case histories? of say a deep groove ball bearing at a fixed speed running 24/7 for example.

Any info/anecdotes with pictures, W/forms or spectrums would make this novice's day.

Much appreciated,

Jonesy.

Hi Jonesey, just got this this morning. Explanation with pictures nice and easy for me to understand

http://reliabilityweb.com/inde...re_stages_responses/

G,day mcdm
Thanks for the link mate, easy reading with a few pics, good stuff. Would 've been good to have the spectrums and waveforms that went with each bearing pic.
Cant have everything at once, I geuss experience will have to fill in the blanks.

Some here may not know what it means to support a scientific hypothesis by evidence as indicated by Danny’s comments(unless I am to just take them as snide comments serving no useful purpose) and others. For many or most of us that work in a business environment it is similar to what might be expected from ones work product where one shows that you have done more than put in the time for the week.

Precision rather than vagueness with regard to what was done and how it was done is to be expected. Phrases like more than xxxx bearings has the ring of sales rather than science, rather it be so or not. If one were to do such a ‘job’ at work one would expect an accounting of the number of bearings, the types (not necessarily a complete list), size ranges, speed ranges, load information (design if available), machine types, etc. In the end one would be able to sort by this information.

What was done and how? What sensors, how they were mounted, and precise working definitions of the measurements would be provided. Then someone else could perform a similar examination and be able to find the same symptoms as the original researchers.

1000’s of bearings would be time consuming and expensive. Many bearings would have to be cut up, not all such as some of the complete failures, whose failure might be obvious. By doing so, the false positives would be identified, the bearings that did not fail but were pulled as well as the precise cause of failure. This would be done in an organized manner.

The results of the analysis would be stated with machinery types, speed, and other with this or these symptoms had xx% failure stage, bb% had failure stage x, etc. This would be the real data from organized test, not unlike what would be expected at work. This is more than it ‘feels like’ so and so; this would be an actual work product.

Without at least seeing a reference to similar information, leads me to not call this a scientific theory. Rather it appears as a hypothesis masquerading as a theory as yet not submitted to rigorous testing.

I would never discount real experience, not just time in grade, of a consultant (in house or outhouse) when making a judgment. However, it is fair to ask for the basis of their judgment, personal experiences or hearsay.

As for Danny doing research for me, I am not usually that trusting with such things as evidenced by these posts, and believe it or not we do have libraries down here in Texas. Not to have a legitimate reference to start makes this difficult. This suggests that there is no reference, which leads to possibly 1) there is no such data or 2) the data is ‘secret’ and kept secret because it is very valuable. I have thoughts on that, too, but I have no facts.

At our plant, in our evaluation of bearing defects, we consider rough published thumbrules, such as from CSI, Nelson Baxter articles, stuff read on the forums. (for example if I see more than 6g's true peak/0 outer race defect and no evidence of accelerometer mount resonance, which could cause a false alarm, THEN I am pretty sure there will at least be visible bearing defect... true peak acceleration useful for judging early stages but not later stages). To my knowledge none of the thumbrules are directly supported by detailed peer-reviewed scientific paper that includes a statistically large sample of methodically collected data and inspection results.

In our evaluation, we also look at trends and sister components. We look at other information; funny noise, abnormal temperature, grease appearance, oil darkening. Also knowledge of speed and loading as predictor of how fast degradation might progress. And we look at the pattern - more than one type of defect evident tends to increase the severity.

None of these items by itself is conclusive. It is certainly acknowledged that there are weaknesses in applying thumbrules since many of the measured parameters cited depend very heavily on measurement technique (location with respect to load zone, accelerometer mounting method, sample rate used in determination of true peak, etc).

In the end it's a judgement call. The more indicattors line up pointing toward the same diagnosis/severity, the higher confidence we can assign to our statements/projections.

We also have the luxury of looking at a fair number of removed bearings. I have had about 30 pairs of bearings cut apart. Each one that we look at in hindsight is a unique story and sometimes nudges our degree of confidence in the various predictive indicators in one direction or another.

Sure I’d like scientific backup. If it's out there I'd like to hear about it. But I don’t know of any so I use the tools that are available.

Some while back you had mentioned ISO. Are there some ISO standards /guidance related to judging bearing defects? I certainly haven’t heard of anything like that, but if they are out there I’d be interested to learn more.

This message has been edited. Last edited by: electricpete,

Bill,

How can you say there is no reference? I have given you the name of the person who developed the Stages of Failure system, the title and the name and location of the guy who published it. I ask again, did you contact them, find out their methodology and find it lacking scientifically? You say it "appears as a hypothesis masquerading as a theory as yet not submitted to rigorous testing." What do you base that appearance on? How do you know it hasn't been submitted to rigorous testing?

Good, reasonable, rational, post Pete.

AFAIK, there are no ISO standards for rolling element bearings. To establish working standards would require addressing the complex issues that bearing condition assessment requires and this is probably beyond the political and technical capabilities of the standards organizations.

No, I don't believe in Santa Claus, either.

Duncan

This message has been edited. Last edited by: Duncan Carter,

EPete,

ISO 15243:2004, Rolling bearings - Damages &
failures - Terms, characteristics and causes.

Sorry! just realised the intent of your question for ISO standards and bearing defects.

The above standard is for the visual analysis of bearings after failure not for judging severity in situ.

Cheers

Ashley

I suspect the bearings are laughing at us..

So, how many angels fit on the head of a pin...??

Bearings don't need this post to laugh at us. I can't count the number of machines that behave like "they didn't read the book."

What book? Some of Charles L. Dodgson's books seem relevant.

Make that "... didn't read the Chart!"

I think WF has to be putting us on. If we are driving a car along a cliff, and we turn the steering wheel in the direction of the downhill side of the cliff, we will end up heading, at high speed, down the cliff. Do we really need to have this documented by a pedigreed paper? How many of us want to see extensive testing performed on this procedure? How many of us want to participate in the study?
I believe we are missing the main source of the numerous bearing failures....the people of SKF, Timken, FAG, Dodge, etc. etc. etc.
They have volumes on bearing failures, stages, faults, etc. etc. etc.
I also feel that they are usually not very helpful in diagnosing a bearing failure for several reasons, one being liability and the other that it is almost impossible at the stage that some bearings are pulled to identify the root cause.
I have always cautioned customers that predicitve can only do so much. A bearing which has just passes a vibration survey could lose a seal the next day, lose all of it's lubrication and the failure will occur before the next survey. And, again, the failure could be so damaging that the failed seal evidience would be lost.