Babbitt

My Grandfather used to:

Melt out the old babbitt first.

Clean the part & rough up the babbitt holding surface just a bit.

Place the part in a custom mold he made.

Pour molten babbitt into the mold holding the part

Let it cool till next day, or till cool enough

Hammer off the mold

File & sand any part he did not like

Put part back into production, or whatever it did.

Still got memories of using extra babbitt to make fishing weights.

Those were the days:

Dear Guest

What kind of bearing? Journal or thrust? The babbit is melt on the bearing base material or is a separate layer? It is forced lubrication of this bearing? What type of equipment? Centrifugal or reciprocating? What rotation? Are to many things to be clarifed before to get a recommendation befoe to act. Waiting for your reply.

Regards

Dear Aurel Mares:

We have a centrifugal turbo-Compressor that works at 3000 RPM.(24 Hr @350 days/year)

We alredy rebabbitted conducted bearing but we are thinking that we can do it whit the conductor(Turbine) Too.

What do you think about?

Thanks for your time

JAIBOGO

It is also possible to thermal spray babbit for bearing repair, depending on the dimensions and size of the bearing. Metal spraying is a line of site process.

You would need to machine and blast the surface, then metal spray babbit onto the bearing before machining back to the required size.

After being cast or sprayed on a babbit bearing has to be scraped to get a fine working surface, to do this you cover the inside of the bearing with a light coating of blue, then you mount the bearing and see where it scrapes the babbit, then you have to scrape the babbit with a hand scraper until it shows an even surface wear. This will normally take some time as you have to try several times to get it right, but it is always best practice to get good wear on the bearing.

Spencer.

We poured new bearings in a Niagra 2 1/2 ton metal stamping press. These were for the crank shaft and are the 2 piece or split style bearings so the bearing caps can be removed. This allows for the removal / installation of the crank shaft. The old bearing material was removed and new material was used for the casting. The crank shaft was coated with soot from an oxyacetylene torch to prevent the Babbitt from adhering to it. The crank was positioned in the stamping press with blocking / bracing. Then the bearing caps were prepared with Babbitt dam. This is a product that is used to prevent the Babbitt from flowing into areas you do not want. Since this is a 2 piece bearing we needed to pour half of it first. It was easier to pour the fixed half of the bearing first for us. The bearing caps were then bolted on and the Babbitt dam was checked to make sure the parting line was correct. More Babbitt dam was applied to create the mold to hold the Babbitt as it was being poured. After the pour and the Babbitt had cooled, the bearing caps were removed and cleaned. The half of the bearing that had just been poured was checked to make sure the pour was successful. Then the exposed mating surfaces of the new bearing and crank shaft were coated with soot from the torch. The bearing caps were reinstalled and the Babbitt dam applied to contain the rest of the pour. When the Babbitt had cooled the bearing caps were removed as well as the crank shaft. All surfaces were cleaned to remove the soot. The caps were drilled for lube lines though the existing ports. The caps were reinstalled minus the crank shaft. Then the lubrication grooves were scraped in. Be sure to check for ridges along a freshly scraped groove before installing the crank shaft. The bearing caps were marked for orientation and then removed. The crank was installed and then the bearing caps were bolted back on. A generous application of lube oil and time allowed for it to flow into the bearing before start up of the press. These bearings were poured some 15 to 20 years ago and are still running. Granted, this press is not run every day. But, it has seen many hours of run time. This job was completed in large part by our welding instructor. I point this out so as not to take credit for his work. I would recommend making a practice bearing before trying the actual job at hand. I am not sure how much shrinkage, if any, occurs when babbitt cools. If you need a very small gap you may need to make a core smaller than the shaft to allow for shrinkage and then machine it to size after the pour.

a long time ago in a place far far away..... I was stationed on a destroyer tender, we had to re-babbit bearing quite often. my best sugestion is to find a small foundry/machine shop. they can take your shells, make a pattern, pour and machine for you pretty quickly.

Check out the website: www.waukbearing.com

Check out the technical literature for download.

Need more help: as on website, contact them in Pewaukee, WI, USA

What is the size of the bearing and is it in 2 pieces? Babbitt is a avery low melting point alloy and any babbitt bearing can be repaired even without removing the worn out coating by the Thermal spray process using Babbitt wire and a wire spray gun, The only pre treatment is some prehea to burn off the oil in the bearing coating clean it with some solvent and then spray and the spray coating will bond fully for machining and a usable bearing as good as new

vshwn7@aol.com.

Vishmayor:

Yes the bearig is in 2 pieces and the diameter is 2 15/16 inches.

What do you think about the lubrications chanels?

Thanks

Jaibogo

The lubricatin channel can be manually cut with a cape chisel after machining the bearing. It is easy as the material is very soft. I have a friend who does this all the time when he refurbishes bearings for antiqaue automobile engines. And if you are in the business of doing such things, I can provide you with the eaquipment and the knowhow for this process.

vshwn7@aol.com

Afterthought. At over 300 HP and high RPM's your oil pressure must be very, very high. I suggest you check with the manufacturer on this. I mention this because of the possibility that low oil pressure caused your problem.

White metal or babbitt metal bearings often don't require a high pressure oil supply.

On ships and power stations that I have been involved with large bearings were often lubricated with an oil ring. This was/is a ring that is about 1.5 times the diameter of the shaft that passes through the bearing. It sits on the shaft and as the shaft rotates it lifts oil up from a sump and splashes or spills it on to the top of the shaft.

The ring is usually made of brass and has a concaved inner surface to lift the oil.

With babbitt metal bearings the old force rule applies, Pressure = Force/Area.

With a big area the pressure at any one point is not so great that an oil film cannot cope with it.

BAB