Babbitt Bearings

Modified on 2011/02/02 11:27 by BobHolcombe — Categorized as: Bearings, Restoration Topics

Babbitt Bearing Information

Many old woodworking machines made before the 1940's contained Babbitt bearings. While many people shy away from machines with Babbitt bearings due to the uncertainty of this kind of bearing, very often you can get a good buy on these machines and if the bearings are in good shape and properly cared for, they are just as good (if not better) than ball bearings.

Even in today's modern age, Babbitt is still being used in some applications over ball bearings. Babbitt is the preferred material to use on extremely large bearing surfaces where the cost of using ball bearings would not be practical. For example, large power generators (such as in a power plant) have Babbitt bearings on their main shafts. Babbitt is also still used on the main shafts in large ships.

Another advantage of Babbitt over ball bearings is that if you have a good tight bearing, it will very often turn more true than ball bearings. For this reason, some precision metal lathes are still made using Babbitt based bearings over ball bearings.

I once read an article in a woodworking trade magazine from the late 1930's where babbitt and ball bearings were compared to one another on a woodworking jointer. To keep things fair, the magazine obtained two identical jointers from the same manufacturer with one exception - one machine had the old style Babbitt bearings while the other had modern ball bearings. The article concluded that after examining lumber face planed over both machines that the Babbitt bearing machine actually had a slightly smoother surface. While the differences were not striking, the main point is that Babbitt bearings are not a bad thing.

Now that you have read the "good" points about Babbitt bearings, there are some down sides. First, Babbitt does require the operator to perform routine maintenance - primarily keeping the bearings well oiled so that they do not run dry. With having to use oil, sometimes Babbitt bearings can be a bit more messy and oil can sometimes get onto the project you are working on. Second, if a bearing is worn beyond acceptable tolerances, the precision that the bearings can give you will be lost and instead replaced with a sloppy finishes on your work.

If you are looking for a machine that you do not have to do anything to but flip the switch, Babbitt may not be for you. However, if you are willing to put a little extra time into caring for your machinery, machines with Babbitt bearings can give you a lifetime of service. And even if a machine needs new bearings poured, the good news is that it is really not that hard of a job for somebody that is fairly handy to do the job their selves. Fortunately for us woodworkers, most of us are pretty handy and are well up to the task.

Besides the articles listed below, useful information on selecting, pouring, and maintaining Babbitt bearings can be found in the Magnolia Babbitt Bearing Book, published in 1927.

Frequently Asked Questions about Babbitt: