View Full Version : Bsbbitt Bearing Question

06-30-2007, 11:39 AM
I am making a jack shaft for my "new" 1909 LeBlond lathe out of a shaft that came off a 14" table saw. The shaft has two 1.30" Dia X 4" babbitt bearnings. One is set up for an oil wick and the other has been modified for a grease cup. I always thought it was a no. no to use grease on a babbitt bearing. Right of wrong? Gary P. Hansen

06-30-2007, 06:55 PM
Grease is ok. We useto build some machines that used babbit bearings in a big cast irin housing .Store bought and they came with zerk fittings on them. I thank Browing made them.. Old engines use babbit bearing with grease cups.

06-30-2007, 06:57 PM
Thanks. Gary P. Hansen

06-30-2007, 07:36 PM
Forced grease cup.. you turn the top lid down to squeeze the grease down into the bearing.

The old cinncinatti has oilers with the clear glass jars on it. My Lebond has flip oil caps.

I am trying to remember where I worked with a lathe, I could pick up the chuck and drop it making a thump.. the babbit was shot out. In a heavy cut, chattered really bad.

07-01-2007, 01:12 AM
They'll last longer if you use oil. Light oil for speed, medium oil for load. Clearance is generally .0015" and grease won't stand up to that. I don't know of any "grease" fed engines with babbitt. Also, use a tin based babbitt (less than 1% lead).

07-01-2007, 02:37 AM
All of my Hit and Miss and Throttle Governed engines that were made up to about 1930, use Grease cup lubrication for Rod and Main bearings. Max RPM was under 650. Newer engines went to lighter flywheels, higher engine speed, and oil lubed bearings....They feel somewhat cheesy compared to say, a 6 HP Fairbanks Morse single cylinder throttle governing type Z of 1922 only 980 pounds of good old American Cast Iron....Almost 2.375 inch diameter babbit bearings on it....With 2, 30 inch Flywheels.

J Tiers
07-01-2007, 09:10 AM
Yep, 600 rpm Jaeger (Hercules)..... all grease cups, with one oiler on the cylinder.

But, it is true that grease generally wants a little more clearance than oil. And it depends on what the surface speed is. I don't know how to figure that for a plain bearing, but a ball bearing has a speed factor which determines the grease/oil choice, and even the weight of oil that is best. Grease is low speed.

it comes down to the "shearing" velocity. There is lube adhering to the fixed bearing, and lube adhering to the journal. In between, there is an area where the lube is "sheared". The higher the surface speed of the shaft, the more "minor circulation" must exist in the sheared area to build up the "wedge" of lube that supports the shaft.

Grease or heavy oil can't shear and circulate the way lighter oil can, and will heat and/or fail to build up the wedge of lube, where a lighter oil might build up the proper "wedge" of lube and support the shaft off the bearing surface.

But at slower speeds, the light oil will NOT build up the wedge, it will simply run out the ends or the lube grooves, allowing the bearing to "wipe". A thicker material like heavy oil or grease is required to stay in the bearing.

07-01-2007, 11:18 PM
The "grease" you speak of was probably 300 or 600W oil; Not the "grease" most think of today. Packing grease was used on VERY low rpm bearings. If you use it 5 minutes a day and "grease" it each use, you should be fine. Otherwise, use oil.

J Tiers
07-01-2007, 11:24 PM
If that was directed to us with the engines, I doubt it.....

The greasers are for a heavy body grease that has to be forced into the bearing. Several "turn-cup" greasers, and one on the big end that is a spring-feed greaser (although mine is missing, replaced with a "turn-cup"). One greasing on big end would go all day, or most of it (farm days are longer).

These things are from 1900 to the 1920's, when grease was fairly well known and ordinary.

I agree though, that the countershaft sounds like an application for oil and a drip oiler, actually. Grease might have been used because it was out-of-the-way, hard to get to, and less likely to get proper care.

07-02-2007, 03:53 AM
A couple of my old engines specify long fiber grease for the rod and main bearings Grease cups...... no Oil..it would sling out and be gone in a couple spins... Remember the rod, and main bearings are exposed on these old engines oil would be a slimy slinging mess all over the place.
Regular motor Oil is drip fed to Cylinder and piston/wrist pin by drip oiler.

Model T Ford rearends from same period use 600 W in rear end, but again a much higher speed application than a 650 rpm engine driving a countershaft...

J Tiers
07-02-2007, 10:08 AM
Model T Ford rearends from same period use 600 W in rear end, but again a much higher speed application than a 650 rpm engine driving a countershaft...

And enclosed....... so the oil doesn't get away. Even 600 wt oil flows, in a way that correct grease does not.

07-02-2007, 10:43 AM
Just a minute.

The "grease" you speak of was probably 300 or 600W oil;
Sure. And 600 Saybolt is equal to 85-90 weight SAE Gear Oil which is equal to 30 wt SAE engine oil. The SAE Gear Oil scale doesn't go to 600 as that would be equivalent to tar.

Grease is oil with a thickener added, usually some sort of soap that acts as an emulsifier. Babbit bearings with grease are still the heavy lifting champs and are used in such things as traveling cranes. The problem with grease at higher rpms is that the thickener breaks down from the molecular shearing. The same happens with the usual viscosity index improvers used in standard multi weight oils which is one of the reasons you should change the oil in your vehicle regularly.

I forgot to mention, most ball bearings can be lubricated with either grease or oil. If grease is used it normally reduces the maximum rpm spec by about 20 percent. The main concern with grease in a babbit bearing would be to avoid extreme pressure lubes. The additives are corrosive to certain metals including copper and zinc. They may also be corrosive to some babbit alloys.

07-02-2007, 02:16 PM
Just a minute.

The SAE Gear Oil scale doesn't go to 600 as that would be equivalent to tar.

You're right again Evan. ;) ... And it is like tar. It's usually sold under the term steam cylinder oil. (And it is 600w.) :eek:

07-02-2007, 04:06 PM
And it is 600w.

ISO 680 Steam Cylinder Oil (the heavy grade) has a viscosity of about 625 centistokes at 40 degrees C which is about SAE gear oil weight 150 or about equal to 60 or 70 w engine oil. ISO 680 steam oil drops from 625 centistokes at 40C to 37 cSt at 100C (not a typo). The effective SAE rating at normal operating temperature is then about 15W engine oil equivalent.

07-02-2007, 04:32 PM
Just went out to garage and looked at the new jugs of Ford T 600W rear end oil...Looks exactly like thick Molasses, Same dark color and thickness almost like honey. I DID NOT try to taste it :)
I have a couple 26 T's that are on to do list.....

I would put it in the almost tar lubricant catagory :)

J Tiers
07-02-2007, 06:37 PM
However, I have worked with 500 cS oil in damper mechanisms....

Yes, it is thick, but it is NOT remotely like grease.

The 500 cS stuff will run off a piece of wire. Takes a while, but it does. You can watch it start, without much of a wait. Grease of most types will NOT. Not for quite a while, longer than you have to watch. You won't even see it collect at the bottom like the thick oil does.

Sorry, but thick oil will NOT work in a screw-down or spring-pressure greaser.