[Steam-engine] Oil Grooves

[Richard Strobel]

Andy, I quote from Gingery's Book: "How I Pour Babbitt Bearings." starting 
on page 33.

  "Bearing Lubrication"

"A continuous even film of oil must exist between frictional surfaces of a 
bearing in order for it to run properly.  The oil film will actually prevent 
the shaft and bearing from touching while in operation.

  If you remember, we payed careful attention to the location of the 
existing oil holes and oil grooves in the bearings for this shaft, so it 
will be no problem to relocate the holes and duplicate the oil grooves.  But 
if faced with doubt, deciding on thelocation of an oil hole or oil groove in 
a bearing is not difficult at all.  In fact simplicity is the key.  As a 
general rule, bearings 6" wide or less will only require a single oil hole 
centered in the top portion or cap of the bearing.  Bearings wider than 6" 
will usually have two oil holes.

  It is common practice to place oil grooves in bearings. And these are 
usually placed in areas of the bearing that are under the least amount of 
pressure.  And usually the area of least pressure is in the top half of the 
bearing. (He now refers to a pix with "X" groove in the top cap..grooves do 
not extend all the way out to the edge.)

  Oil grooves can be machined in, but since the bearing metal is so soft and 
easy to work, it is often quicker to just scrape them by hand.  (I've used a 
dremel with fairly good results)

Oil groove should be cut as narrow as possible in order to preserve as much 
bearing surface as possible.  As mentioned earlier, oil grooves should only 
be cut to within 1/4 to 1/2" of the end of the bearing.

  Since the sharp edges would have a tendency to scrape oil away from the 
shaft, all such edges directly in contact with the shaft should be beveled 
or chamfered.  This would inclue the edges of the oil grooves, oil holes, 
and edges created by split bearings.  Another very important part of the 
oiling scheme is to bevel or chamfer the edgest at both ends of the bearing. 
The beveled ends have the effect of causing oil making its way to the edge 
to collect in the little wedge shaped pocket creat by the bevel where it can 
be pulled back into the bearing by the revolving shaft."

  Hope this helps some and GOOD LUCK

  Best Regards,
RickinMt.