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9A refurb: Need advice on spindle bearing restoration

thenrie

Plastic
Joined
Jan 22, 2011
Location
Stafford, VA
I am in the process of refurbishing my 1947 9A. Pulled out the spindle this week and found the large bearing has some scoring/galling, both on the spindle race and the headstock bearing surface. My thought is to take it to a machine shop and have the spindle polished and the headstock bearing honed. Wondering whether there is sufficient adjustment for this in the headstock shims.

I know I could almost buy a whole headstock for what this will cost me, but I'm hoping that by having this done I can have a spindle/headstock that has been brought back to new or nearly new specs with regard to spindle runout.

I have also thought about doing it myself by using a brake cylinder hone on the inside surface and polish the spindle myself with emery cloths, but I'm not sure what effect that might have on spindle runout.

Advice and opinions would be appreciated.
 
Pictures would allow us to give you some quantitative advise rather that general ramblings on the subject.
And it's a very subjective subject!! The answer very much depends upon the location, type and severity of
the 'damage'. Some folks have posted here in quite a dither and it turned out that the 'defect' was, in fact,
of no real consequence. Pictures please!

Pete
 
Thank you. Pics coming tomorrow. Too cold tonight!

On the spindle, I don't think there is any damage of consequence. Just a light polish will do the job. However, the headstock bearing has some definite scoring near the right end of the bearing surface that I believe needs to be addressed. I think a light hit with a brake cylinder hone would do the job. Just not sure whether that is advisable on a precision surface.
 
I think I'd be leery of embedding abrasive particles in the bronze if using a brake cylinder hone.. and those things are not made for accuracy in forming cylinders. You are liable to end up with a tapered bearing.
Traditional advice is to knock down the high spots on the spindle with an Arkansas stone. It worked for me. I have a '41 with the integral cast iron bearings, some one bought it for me as a gift. My heart sunk when I pulled the caps, but I did as above and she runs fine for what - the last ten years.

Thank you. Pics coming tomorrow. Too cold tonight!

On the spindle, I don't think there is any damage of consequence. Just a light polish will do the job. However, the headstock bearing has some definite scoring near the right end of the bearing surface that I believe needs to be addressed. I think a light hit with a brake cylinder hone would do the job. Just not sure whether that is advisable on a precision surface.
 
Agreed on the honing. The thing you care about is the high spots on the bearings - the really ugly, jagged few. If you just have some mild scoring and no big peaks, good spindle oil, frequently applied, solves many a problem. If you keep it oiled and properly adjusted, it might even improve a bit as you run it. In any event, I gave away a good headstock casting, with good bearings, last year cause nobody would buy it on ebay, so you should be able to find one if you ever get to that point.
 
Here are the photos I promised. As is normal, the photos make things look worse than they really are. The marks on the spindle I can barely feel with a fingernail, so I'm not really worried about them. However, the bearing surface in the headstock (large end) has some scoring that needs to be addressed. I appreciate all the input. I think a bit of touch up with a stone might be just the thing.

Looks like I'm going to be line-boring and bushing the countershaft bearings. One side is pretty bad. Figure I might as well convert both sides over to oilite bushings and get rid of the felt wicks. I'll be replacing the shaft regardless.
 

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As you say, it's hard to see with photos. But compared to others I've seen those don't look too bad actually.
Dress off any high spots with a fine stone or carborundum paper on a good backer and it should work out
OK. Make sure the wicks are good and will supply the required oil.

Which shaft are you referring to when you say countershaft?

I would not be in favor of Oillite bushings as I don't believe they can deliver enough oil on side loaded applications.
I like to see oil going in and oil coming out. It's a flushing action that is important to these machines. Other wise
the shaft is spinning in it's own waste and grinding away the shaft. Now, if the oil system is retained then the
use of Oillite as a bearing material is fine as the flushing action is retained.

These machines were designed back when oil was cheap and wiping it up was accepted practice. Total loss
lubrication was quite common. Modern machines still flush the bearings, but the oil is caught in a sump and
not allowed to run out on the floor!

Take care,
Pete
 
Because the motor pulley is so small compared to the countershaft pulley, most run a pretty high tension on that belt, and that high side load is hard on Oilite. It'll mostly just shorten the useful life. Make sure you don't machine or ream the inside of the oilite bushing, as you're in danger of smearing the structure closed so you don't get as much oil. There are some bronzes that might work better, probably one of the leaded tin bronzes. You could also go to a cogged type motor belt and decrease the tension, I reckon.
 
The spindle and headstock look fine. Make sure there are no adhered lumps on the spindle using a soft file, and put everything back together with clean felts and good oil. Don't put a stone to the bore.

allan
 
That looks SO much better than the spindle and bores on my 13 I mentioned above. The 13 I have been using for 10 years, the one I used to part off 4" *square* cast iron stock (kinda noisy) before I got a mill. The one that the bearings barely get warm when run at top speed.
I'm going stand right up and tell you, those cast iron bearings are better than the bronze ones, SB said so themselves. You would really be doing yourself and the lathe a dis-service by trying to *fix* something that really isn't broken. Bronze bearings of any sort would be a big step down. Oilite would be an even bigger step down. It was designed for bearings that are hard to oil. because it is porous, it is softer than the equivalent solid bronze, and will wear faster. Plain spindle bearings are going to need regular oiling, you'd use up the supply in the oilite pretty quick, then they would wear rapidly.
Just do as the rest of us have, stone the high spots off the spindle and enjoy the best spindle bearings SB ever made.
 
Ok. Just to make sure we are all talking apples vs apples and I'm getting the right questions answered, there are two separate issues I am asking about: The spindle bearing, which is cast iron, no bronze or oilite involved. I think I've gotten some good advice on that and will simply dress down the offending burrs in the bore that caused the scoring in the first place with a stone, and go with that. Shouldn't affect spindle life or accuracy.

The second issue was the countershaft bearings - this is a rear-drive lathe - and we're talking about the shaft the large pulley wheel is fixed to. Again this is a cast iron bearing surface in which a steel 7/8" shaft runs. The right side bore is scored pretty badly and has sufficient clearance that ISO68 oil flows through pretty quickly (I haven't measured the clearance). I have noticed in some of the later parts manuals for the 9" lathes, that South Bend eventually went to a set of bronze bushings in each side, rather than the cast iron bearing surface. Such that they installed a 1" bushing in each side of the 2-1/2" long bore, creating a 1/2" oil reservoir between the bushings - no felt wicks. I have seen this also in other lathes and machines for different applications, but not with this kind of side-loading. I would have expected these bushings to be oilite, but some of you have said oilite would not work well in this application, so I'm guessing South Bend used some other kind of bronze bushings there.

I have replaced the shaft with a 7/8" TGP 1045 shaft. Now just wondering whether I should just leave things as they are and just resign myself to cleaning up a lot of oil, or have the 7/8" bores line bored and install bronze bushings. I have the oilite bushings on hand, but after some of the advice here, am leaning away from using them. The installation I have described should provide adequate lubrication for the bushings and they would likely outlive me, but if that is not an improvement over using the cast iron bearing surface and felt wicks, then there is no sense in making the alteration.

I think I'll just do the same thing as with the headstock and just knock down the burrs and run the new shaft in the existing bores. I can always change it later if I get to wiping up too much oil. Thanks for all the help, folks.
 
A bit of history on the CI bearings v. the bronze. The CI bearings are "war years" lathes. Copper and bronze were strategic metals. SB went to the CI segmented bearings during this period, and stated that they were more expensive to produce, but were better bearings. I don't know about countershafts, but spindles used for the CI bearings were "superfinished".
I would personally not be as concerned about replacing countershaft bearings, they don't affect accuracy. The spindle bearings are the heart of the lathe.
If you want bronze for bearing use, you want SAE 660/C932 bearing bronze - two names for the same thing. Boston Gear carries premade bushings in this material. Realize if you press them in the hole gets smaller. You can allow for this by reaming the bushes by shrink amount before install or after install where you would ideally want to line ream them with a piloted reamer.
You could also bore *just* oversize in the CI and use loctite.
Just be very aware the two holes have to align dead nuts on or the shaft will be very unhappy.

Why don't you upload some photos of the countershaft journals?
 
Thenrie,

I would use just plain bearing bronze, I think it's alloy 660, for the countershaft. But I would do that rather
than continue with the old set-up.

Pete
 
Rudd wrote "A bit of history on the CI bearings v. the bronze. The CI bearings are "war years" lathes. Copper and bronze were strategic metals. SB went to the CI segmented bearings during this period, and stated that they were more expensive to produce, but were better bearings. I don't know about countershafts, but spindles used for the CI bearings were "superfinished".

I use to think this also but South Bend switched to cast iron bearings with the series S lathes starting in December 1939, more than a year prior to the U.S. involvement in WWII.

Vlad
 
Vlad,
No disrespect, but WWII had actually started by '39. France fell in 1940. The writing was on the wall for anyone that wanted to see it, lots of the US public didn't want to.
In May of '39 we withdrew from our neutrality pact with Japan, and gave them 6 mo. notice we would cut off raw materials due to "domestic needs". This didn't actually start till 1940.
U.S. involvement in WWII started much earlier than December '41, by 1939 we were already supplying allies through "cash and carry" and building up our forces as fast as the public would allow. By '39 we had already started stockpiling and regulating strategic resources. See item 2.a and 2.d in the attached Exec Order from Roosevelt in 1939. Exec. Order 8629

Somewhere I have seen a statement from SB that verifies this, and I see you asked about this in April of '09.
I'd say your supposition in the '09 thread was correct. integral-cast-iron-headstock-bearings
 
Rudd,

I'm still not convinced that the change in 1939 was do to potential U.S. involvement in the war. I don't believe that America was yet facing material shortages. I can see that once the U.S. was involved and material shortages where looming that cast iron bearing would become the norm for South Bend.

Per the April 14th, 1931 South Bend bulletin 100 cast iron bearings where available as an alternate to the phosphor bronze on the series N lathes.

Vlad
 
I guess we'll have to agree to disagree on this one. From your last post, if the CI bearings were offered as an alternate (my guess as an upcharge) on certain lathes prior to the war - the phosphor bronze ones were not offered at all during the period in question.
This undated catalog - presumably right before the war since it lists the 11", shows that only the 9" workshop had the CI bearings, all others were bronze. No.95-part2.pdf
Before we run too far afield - getting back to OP's issue, I'd hope you would agree with me that the CI bearings are superior to the bronze ones.
 
Thanks, guys. Loved the history lesson. I'm satisfied that my CI bearings in the headstock will survive me and not affect the accuracy of my lathe. I'm still considering the bronze bushings for the countershaft. Thanks for the material recommendations. The right side is beautifully smooth, but the left side is a little rough toward the ends of the bore. Still, I have replaced the shaft with TGP1045, which tightened up the clearances a little, so it may be fine like it is.
 

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