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9c spindle bearings *pics*

R

raptorfan85

Plastic
Joined
Aug 9, 2015
Hello,

I'm in the process of tearing down, cleaning, painting, replacing felts etc etc etc on my new to me lathe. It's a 1941 model 9c serial number 116449. When i pulled the spindle the bearings looked like they did in the photo. Ive seen a couple bearings on 9's before but not with the grooves cut into them like these... anyone seen these before? Is there any difference from the "normal" style bearings? They are in great shape despite what looked like engine oil that the previous owner put in them....

Thanks
jake


102e862e-85cf-48bb-a197-6d1d8fccc546_zps93iytvbg.jpg
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Integral cast iron bearings used with "micropolished" (or some such) spindle. I.E., there is no removable bearing, it is part of the headstock. Found very shortly before and during WWII. Bronze is great material for warships, cartridges, etc.
I have some on a 13 that was run dry by some PO, has some galling on the spindle. I stoned down the high spots and have driven merrily along for quite a number of years. Plus, no pesky expanders to fiddle with.
 
Thanks rudd. Ive seen the cast bearings on other 9's before, but not with the grooves cut into them like these. They were just smooth. I think that headstock might have been a top oiler though. My memory fails me sometimes.
 
Those are the segmented iron bearings that SB used up to and into WWII time frame. They are a "hydrodynamic" bearing design in which the rotation of the spindle generates oil pressure within the bearing to support the shaft. Kept clean and properly adjusted it is a magnificent bearing system and is probably more accurate and capable of higher speed than the bronze insert system which replaced it. It's downfall was (is) dirt and lack of lubrication. And, unlike the bronze insert system, it if gets messed up it is really impractical to fix it because you'd have to bore it and fit an oversized spindle which would be very hard to come up with.

If you have the system on your lathe and it's in good shape, keep it clean and lubricated and it will last virtually forever.
 
That's exactly what the bearings looked like on my 1944 9A. At over 70 years old, it was very precise with almost zero TIR. It is really amazing to me.

Baxter
 
I was re-reading my Lindsay Publications, Inc. reprint of the 1942 edition of How to Run a Lathe. Found this paragraph you may find interesting.

Why they reverted back to bronze liners (and, by their own statement, to an inferior design) probably had more to do with producibility than anything else. Round bores in the headstock are a lot easier to cut than segmented ones, I suppose.

Hopefully nobody at Lindsay minds me posting this partial page--if so, I'll remove ASAP.

IMG_3832.jpg
 
Does anyone know what the clearance spec should be on this style bearing? My 9C has this type bearing in it and it is shimmed too tightly.
 
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