What's new
What's new

Tilting Pad Bearings

ElCouso

Plastic
Joined
Jul 9, 2017
Hey guys, brief intro to the subject for the uninitiated in the bearing world.

There is a (I want to say modern) type of bearing used in heavy duty machines that consists of a number of pads assembled around a heavy casing. The beauty of these is that they actually move (tilt) and can compensate for small misalignment in the shaft. These are Tilting Pad Bearings and they are used for thrust and journal support (see picture example that I found on the net).

I was thinking about starting to service those bearings (very commonly found in my area) but there is a part of the job that puzzles me: how to apply the babbitt to the pads.

I have been trying to find literature and some science behind this without going to Metallurgy 101 and taking it from there, but I've been fairly unsuccessful.

For refurbishing each bearing I would have to disassemble them completely (for inspection of any internals that may be worn out) and work with each pad separately to keep the job easy. Casting the babbitt on these pads seems a bit impractical, and I've read that spinning the bearing while pouring creates a very good bond between the babbit and the casing, however this would only work for elliptical bearings which have uniform surfaces. Not our case.

I have worked with HVOF before, and I know that there are machines that can spray babbitt metal from wire, I just wonder how well is the babbitt going to stick to the pad. Anybody with this kind of experience?

Any other ways you guys know this can be done?

Thanks for your comments,

Luis

T-Series-Web.jpg
 
Theres a old book on babiting bearings in the down load on here, sticks like solder and its common to TIn the parts prior to casting it on there.
 
I have repaired Babbitt bearings in the past. You need a mold or arbor to confine the Babbitt until it sets up. You also need to get all of the old Babbitt off and tin the casting the casting needs to be heated up to about 500 degree so the Babbitt won't chill. If I remember correctly I learned about it from one of the Audel's millwrights guide's.
 
Theres a old book on babiting bearings in the down load on here, sticks like solder and its common to TIn the parts prior to casting it on there.
Thanks! I'll get my sherlock holmes up and try to find it

Sent from my SM-G930U using Tapatalk
 
The pads have the babbitt applied typically by spin casting, i would not call them Modern, they have been around for 50 years at least. The tilting pad is not there for "misalignment". The thrust bearings are the same, the tilt pads are not there for alignment that's more of the job of the rocker backs. If someone is letting a company loose on their tilt pad bearings that does not understand the physics behind why you have a tilt pad, there is going to be a very lucky sales repo for the OEM, when shit goes south.
 
I was thinking about starting to service those bearings (very commonly found in my area) but there is a part of the job that puzzles me: how to apply the babbitt to the pads.
What others have said. This is not as casual as first appears. "How to apply" is ball-point pen to purchase order that puts the ones most often seen in your stockroom.

IF then you can swap them out faster than the next Pilgrim is able to do, you have a competitive edge.

If they are usually in stock somewhere and ship fast to all-comers, don't even bother with that much.
 
IF then you can swap them out faster than the next Pilgrim is able to do, you have a competitive edge.

If they are usually in stock somewhere and ship fast to all-comers, don't even bother with that much.

Hi Monarchist,

It may surprise you, but from conversations with plant managers around my area it would turn out that they normally prefer to buy a new bearing instead of refurbishing one just because the price of them both would be pretty close.

I am trying to gather as much information as I can and also run some numbers, because I cannot see how this could be so overly complicated that it would cost that much to recondition a bearing. If I can find a way to get them back to spec and still be affordable then I may just've hit a new niche.

These are big-ticket items (shaft diameters of 16" and 18" are pretty common) and they have piles of old ones in pretty good condition but not fit for service anymore because clearances became too big.

The babbitt spray method seems ideal for these kinds of pads, but I haven't heard anyone ever using it before, much less how does it hold up in time.
 
Bare in mind on shit like this, the bearing is the low cost item, crane time, lost production and man hours to swap are the big ticket numbers.
 
Hi Monarchist,

It may surprise you, but from conversations with plant managers around my area it would turn out that they normally prefer to buy a new bearing instead of refurbishing one just because the price of them both would be pretty close.
That does not "surprise me" in any way. I'd do the same. NEW bearings, factory spec, ass covered. Done with that.

"Surprise" would be the reverse. That there already existed an alternative to the OEM whose refurbs lasted longer than new, and had such a resoundingly good reputation I'd have no risk. As may exist in the world. But are not YOU, and probably not on these bearings, nor even bearings in general.

I CANNOT see setting up a refurb op - any product - from a cold-start that could compete on net unit cost with the OEM who have done the research, made the investment in specialized production equipment and testing gear, learned from production mistakes and field-failures alike, applied those hard lessons to changes large and small ages ago, until they got it all nailed-down to routine, easy, and very, very predictable. For themselves. Not for you.

This product, or any other, newbies and fewsies vs established volume specialists also already sitting on the main channels to market is ALWAYS a damned tough game.

I am trying to gather as much information as I can and also run some numbers, because I cannot see how this could be so overly complicated that it would cost that much to recondition a bearing. If I can find a way to get them back to spec and still be affordable then I may just've hit a new niche.
It wasn't "complicated" for Timken to recondition a tapered roller-bearing, either. Only the massive and costliest ever, ever cost-justified that vs brand-new ones made faster in VOLUME. And they were the "factory". Had ROOMS full of rollers already to-hand, could custom finish others to a fine fit when need be.

These are big-ticket items (shaft diameters of 16" and 18" are pretty common) and they have piles of old ones in pretty good condition but not fit for service anymore because clearances became too big.
If you think the shaft diameters and the worth of the goods are "Big Ticket", just go and see what the RPE Metallurgist you'll need for sign-offs charges ('coz you, not the OEM are going tho "own" those rebuilds..) and ask an experienced product Liability Lawyer how much bigger-yet YOUR "ticket" can grow to.

Bearings.. specialized.. already a "niche" type ....more complex than first appears.. a foot and more in diameter.. used on serious-costly machinery..?

Hint: There is No Fine Way you can afford the "openers" to get into this game.

Not even if you are already a millionaire a couple of times over and do not even have to work at all, ever again !

You are just playin' wit' yerself if you believe otherwise.
 
If you think the shaft diameters and the worth of the goods are "Big Ticket", just go and see what the RPE Metallurgist you'll need for sign-offs charges

Who is that RPE Metallurgist? I'm sorry I'm not familiar with that...

(btw the product liability insurance sounds like a good idea to explore)
 
Big chance it is electroplating
And several layers of different alloy
On ships the thrustbearings on the propulsion are according this principale for perhaps of 100 years already
Also I worked on a Herminghausen centerless grinder 20 years ago with a bearing like that The machine was from the 70` ies So not that modern anymore
Also wonder why the OEM or someone else does not rebuilds these While there are several who rebuild big roller bearings I fhink even ********* does that But perhaps these are to small to do so economicly
Peter
 
Who is that RPE Metallurgist? I'm sorry I'm not familiar with that...

(btw the product liability insurance sounds like a good idea to explore)

What you need to GET "familiar with" is a biggie, but simple.

As a time-card-clocker, your "risk" is that others above you f**k the dog so badly you are out of a job for no shortcoming of your own.. but because they've LOST too much business. Or even the whole damned company.

When you are "those above you" - as a shop owner, any size, the NATURE of your risk is exactly the same as what happened in Bhopal, India to - in ONE GO - drive an old, large, respected, and wealthy global company to its very knee-pads.

Bhopal disaster - Wikipedia

Yes, that is "worst case". So are air-bag actuator recalls. Engine resonance tearing the wings right off L188 airliners. Plenty of examples out there.

But only the nature of the f**k-up and the numbers on the bill for it are different for YOUR shop.

Exchange time-card for independence?

Welcome aboard. You've just become a risk-taker.

Now.. try to do your homework, research the situation, make sane plans so you can keep your risks within bounds you understand, can manage, and can AFFORD to chance.

Doing that - between our ears - is every bit as important to earning our crust as what we are capable of doing between our hands.
 
As a millwright I do a lot of babbitt bearing work. I have not seen a tilt pad over 12 inches that I recall. Tilt pad bearings are usually replaced. Journal bearings are rebabbitted. The shops that do this will pretty much have this work sewed up. One day turnaround is not uncommon. Do you want that pressure?
 
Exchange time-card for independence?

Welcome aboard. You've just become a risk-taker.

Now.. try to do your homework, research the situation, make sane plans so you can keep your risks within bounds you understand, can manage, and can AFFORD to chance.

Yeah what you say is absolutely right. I've no plans to quit my day job before I have a coherent plan. I just want to explore what seems like a good opportunity.

We all know that for every good idea there is a good number of other thoughts that just didn't work. It is only a matter of being patient and thinking things through.

Sent from my SM-G930U using Tapatalk
 
One day turnaround is not uncommon. Do you want that pressure?
Well most times that pressure is accompanied with some serious dough, so particularly for me is something I am willing to take


Sent from my SM-G930U using Tapatalk
 
But perhaps these are to small to do so economicly
Peter

Stale donuts bet against good Euros it is simply cost of rebuild vs cost of brand-new, even for the factory.

The value of the salvaged, recyclable materials would have to be very, very high, and would have to NOT be worn undersized or such so as to require a more costly process to correct than making new that were ON size - needed no such "extra" processing.

Ex: Shooters recycle brass cartridges cases all the time. Recycling spent bullets for direct re-use, much less-so. Buggers get deformed. Or worse. Hard chroming back to spec is a non-starter.

:D
 
I thought the MTBF on tilting pad bearings was 1500 years...

Thrust bearing - Wikipedia
Well if they are properly oiled and the oil is changed periodically then a bearing would last you a long long time. It would be normally during startup or shutdown when they see the most wear. Also vibrations tortures them a fair amount. Our preventative changeouts are each 32k hours and they would normally come out looking good.

Once we had a large steamer (300 MW) lose the A/C lube oil pumps due to a blackout, the batteries to power the DC pump were expired and without charge. Long story short the customer lost the rotors of that unit.

Sent from my SM-G930U using Tapatalk
 








 
Back
Top