# Bridgeport Head Bearing Replacement -- Lubrication Advise Needed



## valleyboy101 (Sep 7, 2013)

I have an Induma mill which is an Italian b'port clone from the early 70's. Last month I bought all new bearing for it as some of them were getting a little noisy.  Then last week it broke its timing belt, so i dove in and started the dis assembly.  The old bearings  that I have come across were definitely due for replacement.  The old bearings were all open, while the new ones are all sealed.  On the left hand side of the head there is an oil cup which feeds a tube which runs over and drips oil on the bearings under the larger of the back gears.

My question is do I still need to put oil in the oil cup?  It would just run onto a sealed bearing anyway.  The other thing I wonder about is with the old bearings, why drip oil onto an open grease packed bearing? Doesn't it just wash the oil away.

I would much appreciate any advise.

Michael


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## bjmh46 (Sep 8, 2013)

valleyboy101 said:


> I have an Induma mill which is an Italian b'port clone from the early 70's. Last month I bought all new bearing for it as some of them were getting a little noisy.  Then last week it broke its timing belt, so i dove in and started the dis assembly.  The old bearings  that I have come across were definitely due for replacement.  The old bearings were all open, while the new ones are all sealed.  On the left hand side of the head there is an oil cup which feeds a tube which runs over and drips oil on the bearings under the larger of the back gears.
> 
> My question is do I still need to put oil in the oil cup?  It would just run onto a sealed bearing anyway.  The other thing I wonder about is with the old bearings, why drip oil onto an open grease packed bearing? Doesn't it just wash the oil away.
> 
> ...



I have no experience with the Induma, but lot's of B'port experience.  If you are talking spindle bearings, I would suggest that if you got sealed, you got the wrong bearings.  Aren't many sealed angular contact bearings out there.  I only know of one manufacturer, namely INA, who ever made a sealed angular contact bearing.  That issue aside, the original design with "total loss" oil lube is, IMHO, a superior system to a sealed grease lubed bearing.  Think about it.  All wear debris is carried out with the oil, (as it is slung off the bottom of the spindle onto your t-shirt!).  Only time grease sealed would beat the original, is if you tilted the head to horizontal and ran it for a long period of time.  Since this isn't common, I would stick with the original open bearing, oil drip lube system.  Just my 2 cents!

Bob


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## valleyboy101 (Sep 8, 2013)

Thanks Bob,
I bought the bearings from the numbers in the owners manual and all but the angular contact bearings for the spindle came with seals.  I think that I will take your advise and remove the seals from all the bearings below the oiling point, to allow the oil to run down and keep things clean.
Thanks again,
Michael


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## Richard King (Sep 8, 2013)

In Bridgeport the Angular contact bearings are installed back to back.   with the spacers in between.  The out side ring or race is thinner on one end then the other.  The thick end is called the back   and the thin end is called the face.  I usually use Mobil # 38 Red color synthedic grease  The also call it an aviation grease.  I do this so when the new bearings start up the are lubed.    Rich


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