Spindle bearings

N

NGillem

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Mar 5, 2017
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Hi guys,
I have a small Harvey butterfly sg 48 surface grinder. I'm afraid I'm in need of new spindle bearings and before I dive too deep in it I wanted to test the waters and see what information was out there regarding which bearings may be needed. I know these are a close copy of the Sanfords with the same part number. I do not have any oil cups so I'm assuming they are some type of sealed angular contact bearing I have nothing invested in the machine but would like to see what I can do with it. Thanks for any and all help!
 
Rebuilding surface grinder spindles is really something that should be done by professionals who have clean rooms, vibration analyzers, and other tools of the trade. The spindle needs to be smooth running, have no play, and be accurate to high tolerances for the grinder to do it's best work. $$$$$ That said, I recently rebuilt the spindle on my 1946 B&S 2L grinder in my shop. The previous two master machinists who tried to rebuild it failed. My spindle is a plain bearing spindle, running super light spindle oil with 110 millionths clearance between spindle and bronze bearing boxes. Anyway, I was able to fake the clean room, obtained the special oil (ISO 2!), put on my best professional face -8^), got it working, and it is working fine now. It took quite a few fussy hours of planning and work. I think the Sanfords are all small grinders, perhaps yours is 4x8" by the model number. If you want to tear into it, go ahead, but this is not replacing the wheel bearings on your car. Everything needs to be done right, done carefully, the bearings must be carefully fitted, and everything must be CLEAN(!) as it goes back together very carefully. Did you notice the multiple use of "carefully"? If you take your time, do it right, and approach it with the correct mindset, you will probably have success. The other issue is the price of the bearings. For many surface grinders, the bearings are jaw dropping expensive. Maybe not so much for your Sanford, I really have no idea. If it is running OK, I would leave it alone. If it is failing or failed, well, it is already broken, you can't make it worse than that... Keep us informed of what you do and how it goes. Everybody likes a challenge, and especially something that many say is impossible to do in the home shop.
 
I just did a bit of a web search and found that the spindle on the SG48 is driven by a belt from the motor. Make sure that whatever problems you have are in the spindle itself, not the motor or the belt. Take the belt off and turn the spindle by hand and see what you have -- if you haven't already... On a machine that old, it might just be dried up grease in the bearings. If you have it narrowed down to the spindle, take it apart and see what you have in there.
 
Thank you for your responses and help..... yes the machine does run but it was in fact the loss of the belt that got me looking at the spindle. I have done a fair bit of research and understand the concerns of spindle repair in a less then an adequate environment. Maybe it is just old grease but to my hand I feel flat spots on the races. I just wanted to gather as much info as I can because at some point or another I will disassemble the machine. I know the machine doesn't hold much value and it was given to me so anything I can do I will try! Thanks!
 
I also looked to see if anyone posted the bearing numbers, but no joy...
 
Best thing to do is take it apart and write down the numbers they used then call your local bearing distributor to see if they are available and if there are upgrades available. New bearings for my K.O. Lee were pretty cheap going that route.
 
i used to rebuild high speed spindles and it may be possible to save the bearings by cleaning them and repacking with high speed spindle grease( only pack 1/3 capacity )
 
Hi guys again thanks for all of your comments and suggestions. I had a little time this weekend and stripped down the spindle upon my inspection I found mostly old dried grease, I cleaned everything up to get a closer look and visually I see nothing obviously wrong so I'm going do a better cleaning in the ultrasonic cleaner and get ready for reassembly my question is grease.... Is my best option the kluber stuff I have found countless references on or will any high speed spindle grease be sufficient. I know this may not be the best approach but spindle disassembly is easy enough I dont mind giving it a try. Im sure a microscope would reveal many more imperfections but I can live with that.
Thanks
 
Speaking only for myself, If I found as you described "I found mostly old dried grease" and "but to my hand I feel flat spots on the races." I wouldn't waste my time adding grease. Lipstick on a pig.
 
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