Babbitt bearings

machineman8625 · Jul 12, 2011

I poured babbitt bearings and machined them for 25 years. What little I know about babbitt bearings I would be glad to share. I actually do not know why no one seems to use babbitt for model engineering. Larry

mgbrv8 · Jul 12, 2011

Larry
When you have a ovaled or worn out bore. What is the best way to pour babbitt in that void. I understand I need to blacken the part that I dont want babbit to stick to with a carburizing flame but what do I need to do to prep the other surfice to help the babbit stick to it. Also what is to small of a void to pour into??

Dave

GWRdriver · Jul 12, 2011

Seems to me the best way to do it would be to prep the entire bore and pour in a sleeve of babbit and then rebore to the req'd diam.

machineman8625 · Jul 12, 2011

To repair the oval shaped bore, I guess bore it round 1/16 to 1/8 oversize. You can make the babbitt not stick by painting the area with a horsehair acid brush with stove polish that you can buy at any woodstove store. It is just carbon black powder in a alcohol, or some other quick drying liquid. You can actually paint it a second time. To make the babbitt adhere to steel ,brass , or copper, get some soldering fluid in a small 6 to 8 ounce container at any Ace hardware store. If they don't have it they can get it in a day or two special order. Heat the part with a propane torch until the soldering fluid bubbles when you apply it with a acid brush. Then just tin it(apply solder) with lead solder. Just get a whisper coat and then babbitt will stick to that when you pour it. Larry

JorgensenSteam · Jul 12, 2011

Larry-

There seems to be several schools of thought about babbit bearings.
My Dad used them for 50 years at his lumber facility for all of the fans in the kilns, and according to him, they were the only bearings that would run for very long periods of time for many years. He did mention that they have to be kept oiled.

Another school of thought comes from one of the old steam engine design books from the late 1800's, where one designer noted that while the babbit bearing itself never wears out, the journal or shaft will wear out, and replacing a journal or crankshaft was a much more difficult problem than replacing a bearing.

Charles Porter of the Porter-Allen steam engine fame (Porter designed the first "high-speed" steam engine in 1876 which revolutionized steam engine design for the next 50 years) preferred to run gray cast iron on gray cast iron, and found that to give the very best wear characteristics of all, and far better than brass.