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Removing stain and mild rust from lathe ways - SB 9A

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dansawyer

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#1
The machine is a South Bend 9A, made in approximately 1945. It appears to have had relatively light use and had not been thoroughly cleaned in a long time. I am in the process of removing and cleaning all the 'modules', tail stock, apron, and saddle so far. This has left the ways clear for inspection.
First, there is a small section of surface rust on the tail stock flat about 4 inches from the head. This rust is slightly raised and can be felt by physical inspection. It is unlikely that the tail stock will be used in this area but I would like clean up the rust. How can this best be done? Do the chemicals that attempt to reverse oxidation work or do they just product dust? Will removing the rust leave a hole?
Second, there is black stain on various parts of the ways. They do not appear to have any measurable effect on moving parts, saddle, operation. I have cleaned the ways and the saddle and after oiling the surfaces manually operated the saddle on the ways. From an operational perspective the parts appear to be operational. However I would like to remove the black stain. Is anyone familiar with this form of stain? Is there a way to remove it?
Finally, the far end of the ways on the saddle where the cross slide operates is stained. The stain is most similar to a light varnish. The feel is very different from the near end of the ways. The near end is clean and the feel is like the other clean way surfaces. The stained far end has a smooth drag feel. The stain is not rust. What are practices to remove these build up stains? Thanks Dan
 

dlane

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#2
I would try some scotch bright
 

markba633csi

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#4
Soft Scotchbrite pads and oil + elbow grease, no harsh chemicals or acids
Mark
 

whitmore

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#5
The machine is a South Bend.... removing and cleaning all the 'modules', tail stock, apron, and saddle so far. This has left the ways clear for inspection.
First, there is a small section of surface rust on the tail stock flat about 4 inches from the head. This rust is slightly raised and can be felt by physical inspection.
The tailstock would be cast iron, so the rust comes from pits (and underneath it, there's probably lots of flat metal).
So, I'd wire-brush it (or steel wool), and maybe use a mild steel edge to scrape scale off.

As for miscellaneous stains, a buffing wheel and some rouge won't remove iron, but will take off oxides and stains.
Wax or clingy oil (I'm fond of linseed oil) is a benign coating, won't hurt accuracy and will fill any pits with non-hygroscopic
stuff.
 

Richard King 2

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#6
I wish I had a picture to look at, can you add one? In the old days Mobil Vactra way oil was made with Sulfur and it would stain the ways with a yellow goldish tint and sometimes if machining oil contaminated it would turn black. Now Mobil has reformulated and cut out the sulfur.

I would use auto transmission fluid with steel wool or scotch brite. If you need a little stronger use brake fluid. In some cases I use a flap brush wheel on a power drill on the ways. It looks like a ground way when it's clean. Be careful to use a fine wheel until you get the hang of it.
 

dansawyer

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#7
Thank you for the reply. I have attached a photo of the rust. There are two other questions beyond the rust from the photo. The first is there are some obvious dings along the edge near the rust and along the crown of the v-ways. The ways have been lightly hand honed with a soft stone. There are no apparent high points remaining, I assume while somewhat unsightly they are not significant. Can you confirm. The second are the linear lines in the v-ways. These are likely the result of chips getting caught and scrapped along the way. The v-ways have been carefully and lightly hand honed as well; by feel there are no remaining high points. Overall measurements are actually pretty good. Overall bed ware appears to be moderate. Is there anything else that should be done to the bed itself before reassembly? (there is a lot of cleaning of the apron and gear box.)
 

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Richard King 2

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#8
I would first file the crown of the V way and remove the ridge. Be careful not scratch the ways themselves. Use a smooth cut file There isn't much you can do with the nicks on the Tail stock way accept to be sure they are not high. Hate to say this but the ways show wear. You might be smart to pull off the saddle and stone under the saddle too. Then clean the rust off and then use the flap wheel to shin up the ways. Are you close to Oregon City by chance? I have a friend who lives there who could hand scrape new oil pockets in the bed and under the saddle and tailstock.

If all you can do is stone it, file the ridges first the whole length of the crown and the tails stock edge. Flap wheel it, stone it with a Medium grade Indian stone. If you had my friend or I could teach you how over the net as I have done that before. Scrape for new oil pockets not scrape for alignment. Rich
 

Firstram

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#9
I have used ATF as a cleaning solvent and storage oil for years. Never thought about using brake fluid for more stubborn problems, Thanks!


I would use auto transmission fluid with steel wool or scotch brite. If you need a little stronger use brake fluid. In some cases I use a flap brush wheel on a power drill on the ways. It looks like a ground way when it's clean. Be careful to use a fine wheel until you get the hang of it.
 

Smithdoor

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#10
I put oil on the bed ways,let set for week and use 3M cloth (red) come off.

Dave
 
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