Fix for 9" spindle bearing?

Haven't been around here in a long time...not because I don't like you guys, just that my 9" South Bend has been so reliable that I haven't had any need
I've searched quite a bit but can't seem to find any answers. The bearing closest to the chuck on the spindle/headstock is scored pretty good. I was letting a friend of mine use the lathe when I saw & heard it come to abrupt stop. He was just taking a light cut on a piece of nylon so I knew something wasn't right. It was seized tight, so I disassembled the headstock & saw that the bearing surface was pretty scored & worn. The spindle has a little galling on it but I think it's save able.
So my question is what fixes are there for the bearing? I haven't seen replacement bearings? Being that these lathes don't have bearing caps like the larger lathes are they even serviceable? Can it be bored out & pressed with a new bearing?
Here's a couple pics of the wear

Don't panic.

Use some 600 grit wet/dry to polish out galling out of the spindle.

Pull the oil cups out of the head stock. Clean the wicks, oil reservoirs and headstock bearings with brake cleaner -- flush all the crud and old oil out. Replace wicking if necessary. Look for any high spots in the headstock bearings an polish those out.

Lubricate with an ISO 32 oil or lighter. Reassemble. test.

Report back.

I planned to polish out the spindle, should be ok. The problem with the bearing is its got some pretty deep grooves in it for about the first 3/8" in. Kinda hard to see in the pic. Obviously it was an ongoing issue & didn't just wear that much instantly.

Those radial grooves should not be a problem.

Ok, good to hear. I'll have at it & report back. Thanks guys!

Using sandpaper on the headstock bearings or spindle is probably not a good idea.

Sandpaper, especially 600grit, will leave a lot of the abrasive embedded in the iron, and then it will grind away at the spindle during use.

If you have already used the sandpaper, the you need to clean it as best as possible before running the spindle. Use a solvent with a cloth/paper towel, and keep cleaning until you reach a point, where if you take a clean piece of paper towel soaked in solvent, and you run it across the surface, it looks clean.

Typically, polishing spindle or headstock bearing is best done with a polishing compound or honing stones. "Crocus Cloth" is also an option as it will not leave behind abrasive grit after polishing.

The goal of that kind of repair is to take off any high spots that might have been raised above the original surface level. Any points that recessed below the original surface level, you leave as is. If you try to polish this until everything is a mirror finish, that to get to that point might require taking off too much material which will effect the accuracy.

The reason the spindle stopped is probably due to heat. Either too much friction because the bearing surfaces were damaged, or not enough lubricant. With too much heat, the spindle expanded and seized.

Best of luck.

Good advice, I agree. I only planned to try to polish out any high spots & see if that helps. However the grooves in the bearing are pretty deep. That's why my original inquiry was if there is any way to replace the bearing?

I would use a file to remove any adhered cast iron lumps from the spindle, and polish with a green scotchbright pad. Clean well before reassembly. Don't worry about the headstock bore, other than the cleaning with a non-abrasive and potentially new wicks.

allan

Some grooves should not be a problem. Remember that the bearing surface is kind of long, so even if there are a bunch of grooves scattered around, there is still a lot of the original surface left to support the spindle in it's original position. The purpose of knocking down the high spots is to eliminate friction and restore original clearance between the spindle and headstock bearings. The grooves you leave as is, and they will just fill up with oil.

I've never done a repair like that, but cleaning out the headstock bearing would probably be best done with a honing tool.

Here is a youtube video showing the general idea. Not sure if anyone here tried a repair like that, but it seems the most logical.

https://www.youtube.com/watch?v=oUwC019Ll1A

If you were to try knocking down high spots just by running an abrasive over the bearing surface by hand, than the amount of pressure you generate by hand is uneven, and hence the surface will eventually have an uneven geometry. If you use a rotary tool like the honing tool, than the stones are spinning across the whole surface of the bearing evenly in time, and with equal pressure. So the the amount of material you are taking off from the bearing is consistent across the entire surface. You just have to know when to stop before hitting the original bearing surface and the high spots were taken down. Marking the undamaged areas with dykem/sharpie would probably help.

With the spindle, it would be a similar story to polishing a crankshaft from an engine. You mount the spindle in another lathe, and polish it that way. People recommend using a file and "india" stones, or honing stones will work just as good. Don't try to knock down the high spots by holding the spindle in your hand, The spindle has to be spinning in a lathe while you run a stone/file across it, to be able to evenly take down material across the the spindle. Again, you kneed to know when to stop, and marking undamaged surfaces with ink will be a good indicator.

https://www.youtube.com/watch?v=mHVzyvszbhw

In the video they are using abrasive belts. Not sure if they are regular sand paper belts or something finer than that. But a file with light hand pressure would be a good starting point, if the spindle is badly damaged. And clean clean clean before assembly. Using a soaked paper towel in solvent will more readily pick up any debris left over, as opposed to wiping with just a dry paper towel.

If you have never done any polishing before, practice on something other than the spindle/headstock first. Get a round piece of metal, chuck it up in a lathe or drill press, turn it on, and start polishing with sand paper. Start with 60 grit, then 100, 150, 320, 600, 800, 1000, 1500, 2000, etc.... Run each grit size over the test piece until the finish looks even and scratches from previous size are gone. At each step inspect the surface, take measurements to see how much material was removed, and pay attention to the finish you are getting. At 800grit you it will start getting very smooth. At 1000 grit you are approaching mirror finish. Once your piece looks nice, shinny and perfect, put some damage on it, leaving score marks, with recessed metal, and raised metal. Now try to knock down the raised metal until you reach original surface level. See how you do. Experiment with different files and stones for comparison, and see what finish you get.

Also, the spindle might be hardened, so polishing it might take longer than the cast iron headstock bearings.

Good luck.

Wow, thank you very much for such a detailed response. I know that took some time and I greatly appreciate it.
I actually just finished "fixing" & testing it. I am pretty familiar with polishing so I had done pretty close to what you recommended. I spun the spindle in my Bridgeport & first knocked down the real high spots with a honing stone & then polished it progressively finer with Emory cloth & oil.
There didn't seem to be any high spots on the bearing, just the grooves so I just cleaned it out along with the oil passages. Put it back together, ran & cut on it for about a half hour straight & everything seems good. Better than it was in fact. The bearing area didn't even get warm.
I also think I found the culprit. The wick wasn't sticking out of the spring at all, just even with the end of it. I have a feeling this wasn't getting enough oil to the spindle & the metal spring was actually making contact too.
Thanks again guys, looks like I'm back in business!

Awesome. Glad to hear you're up and running.