Good Earth
starting to spend too much on rocks
Member since November 2010
Posts: 155
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Post by Good Earth on Jul 10, 2014 15:02:10 GMT -5
Buddy of mine picked up a home made 20" saw the other day, and it needs bushings for the shaft. He took it apart this morning and found these. Anyone ever seen anything like this before and have a tip about where to find replacements?
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Post by jakesrocks on Jul 10, 2014 16:18:15 GMT -5
That's a Babbit bearing. Must be off of a very old piece of equipment, because it's the same bearing material that was used in Model T and A Ford engines.
Babbit bearings were poured into the bearing shells as a molten metal and then either aline bored to size, or hand scraped to size with a bearing scraper and Prussian blue ink.
Places that still pour babbit bearing are few and far between. You might look for a place that rebuilds antique car engines. A better option would be to replace those bearings with sealed pillow block bearings.
Were there brass shims between the halves of the bearing ? If so you might be able to salvage a little life out of it by removing a shim on each side, and scraping those burrs of the bearing faces with a pocket knife.
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stephent
starting to spend too much on rocks
Member since March 2014
Posts: 213
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Post by stephent on Jul 10, 2014 18:08:51 GMT -5
Don is very correct...babbitt bearings. More then likely poured. Most were. IF....big IF! cuz it it was poured right it's stuck very well.. the bottom bearing shell will lift--going at it from both ends--(try using air pressure first) you could put a 5-10 thousandths thick piece of brass/copper shim stock under the bearing and ream it back to size after installing the top part. (Just to keep it going until you can find a place to rework it) I've never taken a rind out of an engine myself...but have heard tales from during the depression of folks taking an old bacon rind out and leaving it in the sunlight for a few days to toughen up and then cutting it to shape and using that to get by when $$ and during WWII no parts were available to fix their old jalopy's rod bearings. If you try to use lead solder to put a thin coating on that...it will end up in a puddle along with the bearing babbitt too...out of the shell! Reguardless what ya do...that shaft will need a lick or two of medium to very fine stages of emery cloth to clean it....but NEVER use an abrasive on the babbitt material...it will embed in the soft babbitt. You have to ream or burnish that stuff.
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Good Earth
starting to spend too much on rocks
Member since November 2010
Posts: 155
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Post by Good Earth on Jul 10, 2014 18:51:21 GMT -5
Thank you both for the speedy very informative replies! I figured the setup was old, but poured babbitts are OLD! Looks like a set up with sealed pillow blocks and a big riser is in order. I wonder if this arbor is worth anything to an antique machinery collector?
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Post by jakesrocks on Jul 10, 2014 19:40:21 GMT -5
Thank you both for the speedy very informative replies! I figured the setup was old, but poured babbitts are OLD! Looks like a set up with sealed pillow blocks and a big riser is in order. I wonder if this arbor is worth anything to an antique machinery collector? Unless the shaft itself is badly worn, you could try what Stephent said. Try carefully lifting the babbit out of the bearing shell. Your local auto parts store should have sheets of brass shim stock. Fit a sheet a couple thousandths thick under the babbit. Carefully tap the babbit back into the shell. Go to your local art & craft store and get a small tube of Prussion blue oil paint. Coat the bearings with a thin coat of it. Put the shaft in place and tighten the bearing cap down. Give the shaft a turn or two. Take the bearing cap off and lift the shaft out. High spots in the babbit will have the Prussian blue worn off. Very carefully scrape away a couple thousandths from the high spots. Recoat the bearing with the dye and reassemble the shaft and bearing cap. Then do all of the above steps again. It's a slow process, but you can refit a babbit bearing by hand. One thing that should have been mentioned right from the start. Mark the bearing base & cap with a small chisel mark, so they go back together the same way each time. This is very important. And yes, I've heard of bacon rind being used to replace babbit bearings. Especially the low compression Model T engines. My old man told me of doing it to his car. (He also told me about blowing up outhouses when he was a kid, but that can wait for another thread).
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stephent
starting to spend too much on rocks
Member since March 2014
Posts: 213
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Post by stephent on Jul 10, 2014 22:17:59 GMT -5
Poured babbitts are old technology. But still used in MODERN equipment. It's capable of extremely close tolerance clearances, with a very wide support areas, supporting humongous loads with the right babbitt material. And I figure there's a machine shop within 50 miles or so of where you live that might still do babbitt bearings...maybe. As far as blowing up outhouses...or tipping them over..or farm wagons/manure spreaders on the roof.... first thing...how long is the statute of limitations for that?
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Post by jakesrocks on Jul 10, 2014 22:51:14 GMT -5
Poured babbitts are old technology. But still used in MODERN equipment. It's capable of extremely close tolerance clearances, with a very wide support areas, supporting humongous loads with the right babbitt material. And I figure there's a machine shop within 50 miles or so of where you live that might still do babbitt bearings...maybe. As far as blowing up outhouses...or tipping them over..or farm wagons/manure spreaders on the roof.... first thing...how long is the statute of limitations for that? LOL. Don't think my old man has to worry about statute of limitations. He's been feeding the worms for 20 + years. Me on the other hand, Well lets just say my folks didn't raise any angels.
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quartz
Cave Dweller
breakin' rocks in the hot sun
Member since February 2010
Posts: 3,339
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Post by quartz on Jul 10, 2014 23:13:12 GMT -5
Leather was also used to take the slack out of rod bearings of yesteryear. Babbitt can be repoured right in the shell by using a well-centered piece of shaft, blackened with a real sooty burn from an acetylene torch, and the assembled shell heated to not far below the melting point of the babbitt. A grease groove can be cut in using a die grinder or even a Dremel with a real coarse cutter. Did lots of them when I worked in a sawmill. Really, pillow block bearings would be better, babbitt doesn't like a lot of speed unless very well lubricated {read flood}.
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Post by nowyo on Jul 12, 2014 1:30:11 GMT -5
I agree, if they can be replaced with pillow blocks that would be the way to go. If you need new babbit material it is available from Rotometals.
russ
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