Scraping a big Babbitt bearing

[Thedroid]

I'm working on a project requiring the fitting of a 48" bearing, and it was pretty far off. We're bluing and scraping the bearing with the spoon type scrapers, but it's slow going. I also have a set that look like file blanks, but they have a curve and are hollow ground. These haven't given good results without chatter. The bearing should be good to install tomorrow, but I'd like to be better prepared next time.

I'm wondering if there's any old hands out there that remember any other tools that will take off more than a few thousandths per stroke. Maybe something rasp like.

 

[Provincial]

A Vixen file will take off material fast and leave a smooth finish. They used them for shaping body lead in the old days. A Vixen may be too agressive for your application, and you should practice on a piece of scrap first.

 

[bgott]

Draw knife. http://en.wikipedia.org/wiki/Drawknife

 

[signcrafter]

I don't have any advice but would love to see some pictures of what you are working on and some showing the tools and methods you are using!

 

[vga]

WOW I was a BT in the navy way back when and this is how we fitted most of our large steam driven pump, and FDB bearings. We used what is called bearings scrapers designed for this and this only and if you live near a ship yard/ drydock or a large marine/ boat repair fact you will be able to source a few. A word of caution , go veeeeery slow as you can not add needed material back with out a complete redip of molten materisl after removal!! Persian blue is your best friend on this one. Measure 5 times and scrape 1 time!!!

 

[Steroblan]

Yes, there are specifc tools made for working babbit bearings. I used to see them in McMaster Carr or Grainger catalogs.

 

[djjsr]

Many years ago, the machine shop where I worked had an air powered scraper. It was a short stroke reciprocating tool and I think it had a carbide cutting edge. It cut the time by about 75% and you didn't wear out your arms.

I know they exist but I don't know where you could get one.

 

[jeep450]

How can you post that and not include pics?


Where's the pics!?

 

[A_Pmech]

A Biax power scraper will reduce the amount of manual work substantially.

 

[JASTECH]

Babbitt Bearings = Bunny Balls?

 

[wafrederick]

Babbitt bearing were used in automotive engines until 1953,replaced with inserts in 1954.

 

[Provincial]

Babbitt bearing were used in automotive engines until 1953,replaced with inserts in 1954.

This is a Chevrolet man! The dates are appropriate for a Stovebolt 6, but other makes went to inserts earlier.

 

[wafrederick]

GM last used babbitt bearings in 1953.In 1954,went to insert bearings which are still being used to this day.Last year for the 216 with the babbitt bearings was 1953.The 235 with insert bearings replaced the 216 using babbitt bearings in 1954.

 

[Thedroid]

I've got plenty of pics that I'll post later this evening. I am already using the standard tools for the job, but am hoping someone has done this before and can recommend a tool that will work. I like the vixen files, but I'm wondering how they would work on a bearing for a 48" shaft and almost 2' wide. I like the idea of the Biax, but I think it would really dig in and be hard to control. I'll post some pics after dinner.

 

[2oolhound]

a bearing for a 48" shaft and almost 2' wide

WOW! This is one of those jobs you want to have done right the 1st time.

 

[losttechnician]

I would think the shop in whatever industrial setting you are in would have the right scraper for that application. All of the babbitt applications at my plant have corresponding, specific tooling. Might try and look or ask around and see if they have the right tool.

 

[Thedroid]

This job is done in house, and hasn't been done in years. It's an old plant, and the piece of equipment is over 50 years old. Very few guys around that have done this, and really remember all of the tools and techniques. Procedure wasn't very hard.
Blue the journal, set the bearing on top, rock it back and forth several times, and scrap the high spots. Repeat until desired contact pattern is achieved. We blue checked and scraped this bearing approx, 50 times until we achieved what we we're looking for. Your standard bearing scraper does not remove very much material. I'm going to say around .001 per go around. With the amount of surface area to cover, and considering the bearing weighs 2 tons, thats a lot of work. Someone mentioned the flexible rasp type file being used a long time ago, but no real details.

Anyway here's some pics of the tools and the process.

 

[supersteve]

Awesome.

 

[metaldad]

sweet!

 

[wornoutoldman]

Just slather it with STP and fire her up!

 

[Jawn]

That is one big bearing. What is that monstrosity?

 

[Murphy4570]

That is one big bearing. What is that monstrosity?

My guess would be a power plant generator driveshaft of some sort.

 

[Rust]

Whoa mama!

Babbitt Bearings = Bunny Balls?

Plausable..if you tried to lift it.

 

[redwrench60]

I'd like to see the Plastiguage you use to check that clearance

 

[2oolhound]

That much dye would have lasted me a lifetime! That is some bearing!

 

[rlitman]

Someone mentioned the flexible rasp type file being used a long time ago, but no real details.

One of these?

 

[240sxguy]

wow, that's awesome! Thanks for the photos.

Evan

 

[Provincial]

I have a couple of Vixen files that have a rounded shape to the teeth - meaning if you keep filing the same line, they will cut a round-bottomed groove. I think Vixens were made in a number of different cross section shapes.

 

[CJKaz]

Did the original bearing have oil grooves or pressure dams? Would be very surprised if it is a purely plain surface. Good info here:

http://www.kingsbury.com/pdf/catalog-FPJ.pdf


The scraper in the photo was my weapon of choice. Not unheard of to spend several days fitting the bearing. What is the old girl? Synchronous motor?

 

[Thedroid]

Yep it took a total of 5 days to get scraped, and it still could have used a few more rounds. The machine is a Ball Mill, and it's driven by a Synchronous motor. Total weight of the mill is approx 150 tons. No oil grooves, just the dished center where high pressure lift oil is plumbed in.

I looked at the Biax info, and they do make scrapers for Babbitt. Sure would like to try one and see how it did.