Babbit bearings

[bandmiller2]

In  restoring an old  mill would it be prudent to replace babbit bearings with ball or roller or are they ok if adjusted right.I know you have to tell your smith which you have when he hammers the blade,they run a little hotter.Thanks Frank C.

[jason.weir]

I'd keep the babbitt but thats me.

If its in good shape or has enough shims where it can be scraped back to where it should be you can't go wrong. 

In my opinion babbitt should not run hot (no hotter than any other bearing).  If it is, it's either not getting enough oil\using the wrong oil or the clearances are out of wack.

Very simple technology and if properly maintained will not only hold closer tolerances but will outlast ball\roller bearings.

What we typically see today is babbitt that has been terribly abused and not maintained and\or poorly repaired.

I've got an old 20" Baxter Planer (Lebanon, NH 1879) that had worn out\abused babbitt that had been re-poured with what seemed like wheel weights (lead).  After re-pouring and fitting proper babbitt material that bearings run cool to the touch.  IIRC this thing runs in the 2000-2500 rpm range and I can hold my hand on the bearing cap after an hours running time.

Plus it is fun to pour..

-Jason



 

[Dave Shepard]

Our Baxter was retrofitted with two ball bearings on each side to replace the babbit. The blocks were machined out to accept them, and after running for a while, they ger pretty hot. The head was changed from a two knife square head to a four knive round, and the new head had the ball bearings. I'd have stuck with the babbit. It turns 3600rpms.

A friend of mine does  alot of babbit work on old equipment, especially single cylinder engines and line shafting. I recently found him a 25 pound bottom pour ladle, that a big bearing.  ;) It is a lot of fun to work with, you wouldn't think something so crude could work so well, but it does.


Dave

[Ron Wenrich]

I think a lot would depend on how much you're going to use it.  If you're only going to be sawing a little bit, then I'd stick with the babbit bearings.  But, at the least, I would have them repoured.  You don't want to be dealing with problems the last guy had or created.

Typically, the problem lies at the saw end.  When they get worn, you can have some movement on the saw end, and that will cause all sorts of problems.

I do know of guys who run them and haven't had any problems.  All a matter of maintenance.

[rewimmer]

Through the years I have replaced the babbitt with bronze bushings and added a oil drip system on different pieces of equipment. You can turn the bronze outside to match the ID of the housing and usually leave about .004 to .006 clearance between the shaft and bushing. You need clearance for the lubrication and expansion from the heat. Usually a 80 to 90 weight oil worked ok depending how good your alignment between the bushings was and the temperature. You just have to watch it real close to start with and see if it is not going to overheat from all of the above.
Robert in Virginia

[Chris Burchfield]

I repoured babbit bearings on a 1923 Fairbanks Morse flywheel engine. It had belonged to my grandfather. I had the shaft ground smooth at an engine/head shop. I made wood forms for the outside. Steel wool  wrap for the inside. Heated the crank in the gas grill till it was just hotter than I could handle it without gloves. Thus with gloves, placed it in place and poured the babbit.

There is a farm grade babbit and an Industrial babbit. The Industrial is much more expensive. I got mine for free from a friend who's company replaced industrial babbit bearings that became worn or cracked.

Babbit melts much like lead. You clean the floating trash off and discard. Using the clean babbit for the bearing. Hope this helps. Chris B. Memphis Tennessee

[bandmiller2]

Probibly give the babbit a chance,the good babbit is almost pure tin,cheap stuff has alot of lead.I had a john deere A that was a transition model just before the 60.It had aluminum bushings for main bearings different from the 60 and JD didn't sell them.Tried to find al. to machine bearing,to cheap to buy the big piece.Made a wood core mixed up some babbit poured and machined it to fit the crank shaft,that was 15 yrs. ago its still running see it at pulls all the time.Frank C.