Replacing bearings in my Live Center

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TORQUIN

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I have a Ready Tool 240HD live center which has developed some play and roughness in the bearings so I pulled it apart to fix it. The existing bearings are SKF 7206-B, a brass caged bearing that is open on the sides, and a New Departure Q30206 thrust bearing, which is also open on both sides. The center's housing has no grease port in it, so I am wondering if I should try to hunt down sealed bearings to put back into the center, or stay with what was in it already.
If I keep what was in there, I suppose I will just pack it with grease as best I can before I put the screw-on cap back on.
Ideas appreciated.

Thanks,
Chris
 
TORQUIN said:
I have a Ready Tool 240HD live center which has developed some play and roughness in the bearings so I pulled it apart to fix it. The existing bearings are SKF 7206-B, a brass caged bearing that is open on the sides, and a New Departure Q30206 thrust bearing...
Click to expand...

Give it a little solvent wash and feel the bearings; if they're bad, it's easy to tell when the lube is gone.
Try to find a local bearing supplier and get a name-brand if you need replacements, 'cuz there's
a bunch of counterfeiters of these things.

New Departure went out of existence about 1965. Half a century is all the life you
should expect from the grease, so definitely mark 2067 for another lube check, and pack more in.

Unless the bearings are loose in the body, or it has bent the arbor, it's likely the center is OK, but could benefit
from regrinding (assuming it's hardened, most are) after you get it back together.
 
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Just did the regrind on it, and the thrust on the tip was a 32nd, or more, and I decided that was too much. I mounted it and it has .002 run out, which is too much.
I will try cleaning them out first.
2017-12-29 16.19.58sm.jpg

It was a nasty looking tip when I started.

2017-12-28 18.39.42sm.jpg
Thanks,
Chris
 
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Cleaned them out and the ND is still rough. Gonna need a new one. As I have been searching the internet for more info, it seems that my Q30206 is actually the same thing as the 7206-B. Have not yet found definitive proof, but VXB says it is. The new 7206-B's should be here tomorrow.

Chris
 
According to my old Bearing Interchange guide, they are both the same bearing. Sounds to me, someone has been into this center before and replaced one of the bearings. It is far unlikely that Ready would have mixed bearing brands in the same center.
Ready is a good 'old school" name brand for live centers. I've seen some very old ones out there that are still running good as new. My family had a large Ready center we used to use on the bigger lathes we had back then. I have one here in my shop that is has a special point installed. It is replaceable, and it like yours, has bad bearings in it. One of these days, I'll take it apart check it out.
 
Does that center have a bearing at the end of the shaft?
 
Two bearings up front and one, like a clutch pilot bearing, in the rear.

Thanks for the info. I can't seem to find a good old bearing cross reference on the internet, and an old book has not crossed my path yet. I'll certainly snatch it up if one ever does.

Thanks,
Chris
 
New bearings are great, but I cannot get the spindle ground true. The center runs out .002. I took it back apart and turned a holder for the monoset that held the center spindle on the bearing surface. Turned it all at once in the lathe but the holder had .0025 runout. I rigged up a cylindrical grinder in the other lathe and ground the OD of holder but could only get that to .001 runout. I am thinking of making another holder out of different material, as the holder I made was of 1018 and it did not grind well. It looks like a very fine hammered finish after grinding. I figure that's why I can't get it to 0 runout.
If I make another, I will grind the last of the ID in the Monoset so it runs as true as the workhead there.

Chris
 
I took the tip out of my center to grind it.I put it in a collet and ground it. Still left some chowder marks in it.
Mine has 2 bearings, a tapered thrust bearing, the end of the taper has a grease fitting.
I still haven't ordered new bearings, been about 2 years. I have quite a few other centers.
Are you sure your bearings aren't adding to your problems. if they are shot, your tip will be off after grinding.
 
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