9" Headstock Bearings "Stick-Slip"

Hello Guys, I'm kind of new to the forum, so bear with me. I have a 9" (model B) that was made in the forties, and I purchased it from the original (hobby use only) owner. It is in really nice condition overall, only about .007" backlash in both the compound and cross slides. It has never been apart (never rewicked, etc.) as far as I know. I have owned it for about twenty five years, and really did not realize the importance of the correct lubricant oils until I came across this forum. So, I pretty much used whatever oil was at hand for lubricating the lathe, 10W-30 automotive oil mostly. Pretty stupid, I know that now...I recently obtained the correct oils. My question has to do with the headstock bearings. The spindle rotates very smoothly once it IS rotating. Smooth as can be. However, it "sticks" a bit when at rest. You can feel this when spinning it by hand. Sticks ever so slightly at rest, then spins very smoothly. So, if spinning by hand, stick-slip. Do you guys think there is a problem, or is this something I do not need to concern myself with?

as it should be.
probably overkill, but I have developed a habit of rotating the spindle by hand before tightening the belt and turning it on.
it is always just as you describe when I first turn it.

A small amount of "sticktion" can be acceptable. Your headstock bearings may be just a grunt tight but,
If they aren't heating up in use, I wouldn't worry about it.

South Bend headstock bearings are a constant source of discussion around here.

Frank

As designed, the plain bearings on a South Bend rely on a uniform film of oil being distributed over the entire bearing surface of the spindle... which only occurs when the spindle is turning. At rest, the spindle will settle slightly in the headstock. If motor oil or other non-machine oils were used, it's probably a bit gummy on these bearing surfaces and it takes more pressure to get the spindle started on this thicker film. Since it is a simple task, it would be better to pull the spindle, clean everything out thoroughly and then refill with a high grade spindle oil like the Mobile Velocite. You can also relube the spindle cone for the back gear at the same time. Frank's suggestion on checking the bearing clearance is a good one once you have the right oil in the headstock. Steve

SWBrooks said:

As designed, the plain bearings on a South Bend rely on a uniform film of oil being distributed over the entire bearing surface of the spindle... which only occurs when the spindle is turning. At rest, the spindle will settle slightly in the headstock. If motor oil or other non-machine oils were used, it's probably a bit gummy on these bearing surfaces and it takes more pressure to get the spindle started on this thicker film. Since it is a simple task, it would be better to pull the spindle, clean everything out thoroughly and then refill with a high grade spindle oil like the Mobile Velocite. You can also relube the spindle cone for the back gear at the same time. Frank's suggestion on checking the bearing clearance is a good one once you have the right oil in the headstock. Steve

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Thanks for the suggestions. I did remove the headstock oil cups recently (this was prior to my original post) and flushed the reservoirs multiple times with WD40, 70 years of "funk" came out of there. Funk is probably an exageration, as it really was not too bad considering this is likely the first time this had ever been done. Some discoloration/dirty oil, that's about it. Refilled with the proper oil (NO more 10W-30 automotive oil!!), ran the lathe for a minute or two and drained/refilled a second time to hopefully dilute any remaining WD40. It could be my imagination, but the "stick-slip" situation seemed somewhat less after this process with the proper oil in there. I'm thinking it was as SWBrooks described and the automotive oil was causing the "stick" part of the equation. I hope it was OK to do this flush of the reservoirs with the WD40. If you guys think I really need to pull the spindle and do a thorough cleaning/rewick of the headstock bearings, I do have the ILION book, but would need to obtain some new wicks.

I think it would be a good idea to pull the wicks. I doubt that one cycle of flushing got all the wd40 out (soaked into the wicks) and it could be thinning the oil. They may not need changing, but they are available on ebay and maybe other sources. I bought the full kit and rebuild book for my 10L off ebay and it is a nice product. I think the seller is a member here. Rebuild Kit for 9

South Bend headstock bearings are a constant source of discussion around here.

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I have noticed this, but, I'm still kinda confused. Some people say taking apart the headstock is no big deal, others say it is, and to be careful. (Is there a difference between "taking out the spindle", and "completely taking apart the headstock"?) Actually, I guess there is a difference there. Removing the spindle would not give access to the wicks, would it? I have not heard yet of any warning signs of failing bearings, or wicks. How do you tell? Also, does anyone change the bearings out for modern roller or taper bearings, or anything, avoiding the wick problem altogether?

Removing the spindle will allow you to change the wicks, there is not enough room in the headstock casting for roller bearings. Unless you have an under drive lathe you really don't have bearings in the traditional sense, the bearing surface is cut in the iron itself.

Just FWIW, I have never used the proper oil in my 10R headstock bearings.. I was too cheap and didn't have time to wait for it to come "mail order". I use 0W-20 synthetic in mine or 0W-10 if I can find someone local that has it in stock. I have never had any issues with the bearings, even in cold weather. I have even pulled the bearing caps just to see if it is oiling properly, and found NO lack of oil to them. Never had problems with the bearings heating up or anything else, even after long runs or in cold weather.

I know that many out there will piss, moan, and bitch that I'm an idiot, but I know what works fine for me. I don't necessarily reccomend this to others, but it was one of those "necessity is the mutha of invention" deals. When I got it the reservoirs were empty and I had a job for it and had to use it. I didn't have time to wait for the right stuff. The biggest thing is to use an oil thin enough to flow through the wicks and on to the spindle shaft. In this case thicker is NOT better. Sometimes you just gotta do what you gotta do.

If you have one of the ones with the steel shaft in the cast iron bearings, a little zinc additive wouldn't hurt either. (anti scuffing agent)

Just my $.02 worth

Frank

the bearing surface is cut in the iron itself.

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What?! They did this? I thought almost always, a shaft sat in either roller bearings, or a bushing made from bronze. So that when it wears out, you can replace the bearing/bushing. How long does it take for the cast-in iron bearing to wear out? And once it does, wouldn't the whole head be junk?
The lathe I have is a '43 model 10L, with the motor down in the cast iron pedestal, BTW. So is removing the spindle to replace the wicks an easy task, or no?

I don't recall saying bronze is "magical". Just that if the bearing wears out, there is an original surface to put a new one on, and also that the bronze used in bearings is porous, allowing oil to soak in, a good thing.

...... So is removing the spindle to replace the wicks an easy task, or no?......

Yes , it is very easy .
Read this : http://www.practicalmachinist.com/vb/south-bend-lathes/16-sb-spindle-bearing-question-s-128253/
from thread " Noteworthy threads " at the top of the South Bend page .

there is nothing cheap or inferior about the cast iron bearing SB headstocks- arguably the best ones even given less parts to move around- if kept lubricated they may well last forever.

I have a theory that South Bend moved to cast iron bearings in WWII as bronze would be in a shortage due to the war effort. Pre war all lathes where using bronze bushing including the 9" lathes. Post war they went back to bronze bushings except for the 9" lathes.

My 1934 catalog PDF shows that all lathes, 9" and up, used bronze bushings or bearings.

My 1942 catalog PDF shows that all lathes are using cast iron bearings with a super hardened and finished spindle.

My 1943 catalog PDF declines to mention the spindle bearing material though it does describe the super hardened and finished spindle.

My 1948 catalog PDF indicates that all 10" and greater lathes are using bronze bearings again. Which leads me to believe that the 9" lathes are using cast iron bearings.

My 1952 catalog PDF shows that all 10" and greater lathes are using bronze bushings and that the 9" lathes are using cast iron bearings.

Is one bearing type superior to the other? I can't say though those with bronze bushing can have the bearings replaced if their is an issue with them where as the cast iron bearings would require the replacement of the headstock if the bearings go fubar.

My own lathe is a 42/43 heavy 10. I say 42/43 as it was ordered October 22, 1942 and shipped January 4, 1943 to the Marietta Airplane Assembly Plant in Marietta, Ga. The Marietta Airplane Assembly Plant was built by the US Government in 1942. This plant was used by Bell Aircraft Corporation to build B-29 bombers. 665 B-29s where built ther by the end of the war. At the height of production over 28,000 employees where there. I don't know what parts my lathe made for these bombers but i think that it was quite cool that it was used for thewar effort.

Professional machinsts look down their noses at these South Bend lathes as nothing but tools for the hobbyist forgetting that at one time thes lathes where considered professional quality commercial production lathes.

It is ironic that my lathe was purchased from the widow of a fellow that used this lathe to build experimental aircraft. He died not knowing that this lathe was initialy made for the manufacturing of aircraft parts.

Vlad

Hmmm, so it looks like I have a lot to learn about bearings, huh? At this point, I find myself hoping the machine I'm getting has cast iron ones. Vlad, my machine is 1 year younger than yours. It was bought by a company that made watch hands, and hands for instruments in general. Not as cool as yours, but cool nonetheless.

Professional machinsts look down their noses at these South Bend lathes as nothing but tools for the hobbyist forgetting that at one time thes lathes where considered professional quality commercial production lathes.

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That's stupid. I say the only reason they're hobbyist machines now is that they're admittedly outdated, compared to modern machines. Still built better, though. Most of the machinery we have at work is old and tired after less than 20 years, sometimes less. And repairs are frequent. You have to admire a machine built out of a big chunk of cast iron, and meant to go the distance, AND be repaired if needed. Not seen as much today. Oh, and no plastic on them, either!

Nobody's mentioned this yet but your best bet is to first off check the clearances in the bearings
as discussed in the manual. Be sure they're set to the correct value.

If you are getting total loss (that is, oil does dribble from the bearings when in use to some
small degree) then things are probably fine.

As far as "when do those cast iron bearings wear out" well the answer is, nobody knows.
Nobody's simply 'worn' one of those out. We'll have to wait for another few centuries I
guess to find the answer.

just FWIW, I was out in the shop today doing a little tinkering on the mill. Keeping this thread in mind, I walked over to the 10R and gave the chuck a manual spin. I had absolutely no stiction and it spun smooth as a baby's butt. No stiction, no bind, nothing. But the 10R has bronze spindle bushings, not cast iron.

Frank