Machinery's Industrial Secrets
Babbitt Bearing Techniques
These
days we use bronze bushings, ball bearings, and roller bearings. At one time,
though, bearings were cast from Babbitt metal, an alloy of tin, antimony and
lead. It was very similar to type metal used in Linotype machines or solder.
It was also called soft metal or white metal.
Modern knuckleheads laugh at Babbitt. It "couldn't possibly"
be any good because it is so soft. "Only modern bearings" are any good. Bull!
It was excellent bearing material, but the main reason we don't use it these
days is because modern bearings can be much smaller to carry a given load,
need essentially no maintenance, and they're now mass-produced making them
cheap. 
A hundred
years ago, Babbitt was king.
Many people are not familiar with the technique. For instance you might have a cast iron shell for a pillow block. You place the drive shaft through the shell and center it with a simple jig. You melt Babbitt with a torch (propane will do) and pour it into the space between the shaft and the shell. In a couple of minutes the metal has frozen, and you can remove the shaft and check the result. To use your homemade pillow block just put the shaft back into the bearing being sure to supply adequate lubrication. It will run and run and run. It's cheap, fast, and inexpensive. And it performs. Some of the finest lathes ever made had Babbitt headstock bearings.
These
articles from early issues of Machinery Magazine reveal discussions among
WWI era machinists about their techniques, secrets, and discoveries. Topics
include: Making Babbitted Bearings in Halves, numerous Babbitting mandrels,
centering jigs, special jigs for special jobs, Babbitting and Planing Cross
Head Gibs, a variety of Babbitt Bearing Molds, Use of Soft Metals in Machinery
Construction, Anchoring White Metal, Lining Bearings with Babbitt Metal, Babbitted
Machinery Construction, Alignment Babbitting, Babbitting Cross-Heads, Lining
Cast-Iron Bearings with Babbitt Metal, Standard Babbitt Specifications, Babbitting
Fixture for Small Bearings, Oil Channels in Babbitt Bearings, and more.
These
articles are full of drawings, how-to, arguments among machinists, experiments,
discoveries, and experience. Babbitting is something to learn about and use.
Afterall, most early 1900's engines - marine, airplane, steam, automobile
- used Babbitt in their bearings for good reason.
Interesting booklet loaded with old-timer's secrets. Great ideas. Get a copy. 5-1/2 x 8-1/2 booklet 48 pages
No. 22440 ... $5.95
from a March 1917 letter written by "FBJ" to Machinery Magazine
"...It is common practice to babbitt the main bearings of marine engines, and this material gives entire satisfaction, notwithstanding the enormous weight of the crankshaft and other parts, connecting-rods, crossheads, pistons and piston rods, to say nothing of the extra weight brought to bear by the steam pressure. Yet a marine engine must run continuously from the time the ship leaves the port until she docks again, for it is exceedingly dangerous to stop a ship for repairs when there is a heavy sea running. Marine-engine main bearings that are babbitted often run for many years without attention, aside from a little scraping and adjustment of liners, and when they are worn to a point that demands renewal, they are replaced at a comparatively trifling cost.
In the past, many machine-tool builders employed babbitted bearings in lathes, screw machines, small milling machines, etc., with very satisfactory results. In such cases, the babbitt is poured over a mandrel somewhat smaller than the desired finished size and later is thoroughly peened. The bearings are then bored and line-reamed. This method gives excellent results, as any mechanic of the older school can testify. Yet the purchaser of machinery at the present day looks askance at a good, honest babbitted beating, thinking that it is a sure sign of cheap construction...
The babbitted bearing has earned for itself an established place in the mechanical world, and engineers, designers and those who contemplate the purchase of machinery should investigate its merits before hastily condemning it..."
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