# South Bend Class Lathe Spindle Bearing



## electrosteam (Apr 2, 2009)

Hi,
First post by a new member.
I have (in Sydney Australia) a close relative of a South Bend 9A lathe with bad bearings in the spindle.
It is a Sheraton, made in Melbourne, with spindle running in the cast iron housing.
Housing is single bolt closure onto a solid aluminium shim.
Spindle not extracted but can see significant scoring.
Still capable of good work on free-machining steel.
I expect to grind the spindle one day, bore the housing and fit a bronze bush.
Would 3 mm wall thickness for the bush and 0.005 mm off the spindle be likely to do the job ?
Any other suggestions ?

Happy machining,
John


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## rake60 (Apr 2, 2009)

Welcome to HMEM John.

The spindles in the South Bend lathes that I have seen have
a bronze sleeve bearing that is keyed to the bearing cap.







I never measured one to see what the wall thickness actually
is, but don't think 3mm wouldn't be too far off.

Is the current bearing in your lathe babbitt?
How is it lubricated?

Rick


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## Maryak (Apr 2, 2009)

John,

Welcome to our forum. 
	

	
	
		
		

		
		
	


	




Best Regards
Bob


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## miker (Apr 2, 2009)

Hi John and welcome.

Is this the beast?

http://www.lathes.co.uk/southbend9-inch/page25.html

I am in the Hawkesbury Windsor area.

Rgds


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## electrosteam (Apr 3, 2009)

Hi Miker,
Yes, the photos are virtually identical to my machine.
I am near Penrith, send me a message if you would like to chat about lathe problems.
I notice in my original post I wrote 0.005 mm, that is way to optimistic for the grooves I can feel through the shim slot with a thin wire probe.
The spindle may need 0.5 mm.

Thanks rake60,
I can now plan on a 3 mm thick bearing bush.
Lubrication is by manual oil points on top of the bearing housing.
I will change these to, possibly, forced oil feed from a timed pump.
There is no oil reservoir and the bearing eats oil at a great rate at the moment.

My current job is to bore out for axles on four wheels for a 5 inch gauge electric loco.

Happy machining,
John.


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## BobWarfield (Apr 3, 2009)

I really like those bronze bearing setups. They seem capable of great accuracy, often better surface finish than the ball bearings, and they're dead simple. The only disadvantage I can remember reading is they are somewhat rpm limited.

What I don't get is why nobody builds lathes with these bearings and some kind of pressurized oil lube, the way a car engine works. They're certainly capable of rpm. Maybe there are such lathes and I just haven't heard of them. In fact, as I think of it, Rake90, I bet those really big lathes you work on maybe are that way? Or do they just have huge honking big ball bearings?

Cheers,

BW


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## raym 11 (Apr 3, 2009)

what its worth dept.;

At some time in my other life I was involved in installing 10" pressure lube bronze bearings on large diameter overhung fans. There was a reservoir on the roof that provided gravity pressure lube during spin down in case of power failure. 

Ray M


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## rake60 (Apr 3, 2009)

Actually the vertical boring mill's table in my *Large Scale Threading* post,
turns on a ball thrust bearing that is about 6 feet in diameter.
A smaller vertical we had there used tapered roller bearing to support the 
table spindle. I did run one vertical that used a large flat brass thrust washer
type of a bearing. As the table speed increased it would draw more oil to the 
bearing surface ever so slightly changing the height of the table. When finishing a 
face or fussy length, you had to take 2 finish cuts to be sure of where that
face or step would be cutting at that speed on that day.
It really wasn't the best engineered system.

In lathes, babbitt spindle bearings have been used for a LONG time!
This little lathe was built in about 1891. It had a 10 foot face plate
turning on a spindle in babbitt bearings. 




You have to wonder how a material that can be scraped away with 
a fingernail could support that kind of weight, but it DID and still does 
in some machines.

Rick


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## pete (Apr 11, 2009)

Actualy the spindles float on a oil "wedge" exactly like gas or deasle engines built today, I used to drive 18 wheeler freight trucks and some well maintained engines had over a million kilometers on them. If you do the math as a very conservitive estimate then 1 million kilometers = approximately 600,000 thousand miles, At 60 miles an hr. and 1500 rpm these engines had done 10,000 hrs at 1500 rpm, That is 90,000 revolutions per hr. of service. All this on a oil wedge of less than .005 thick.

Pete


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