Lathe Refurbishment (minor) and Maintenance

[Jim Azelton]

I got a second hand G4000 which runs but needs some TLC—mild surface rust, old/crusty oil/grease and chips throughout. I’ve run it a little bit, just to check function but I want to go over it and clean/fix whatever may be needed prior to running it regularly.
I’ve seen to NOT used compressed air to clean because it may drive chips into inaccessible areas but otherwise, what are some do/don’t tips? I’m using ScotchBrite and wire brushes to remove rust and crud as well as parts cleaner (Brake Clean). I have also thought that I may be able to improve slide movement if I carefully break the edges on the slides/steady rest—just enough to remove burrs or “snags” but NOT significantly enough to change the dimensions.

Tips, suggestions and corrections are welcomed—thanks in advance.

 

[extropic]

Welcome to H-M.

On precision surfaces, like ways and dovetails, I'd start with single edged razor blades to remove light surface rust and any crud.
Maybe a final wipe with purple Scotch Brite.
Staining - who cares.
Brake parts cleaner is a good solvent. Use on a shop rag or towel to get the most out of it. Even WD-40 works OK to clean up accumulated sludge.
Don't be in a hurry. pray things down and give it some time to soak in.
After cleaning, be certain to lube everything well

 

[Jim Azelton]

Welcome to H-M.

On precision surfaces, like ways and dovetails, I'd start with single edged razor blades to remove light surface rust and any crud.
Maybe a final wipe with purple Scotch Brite.
Staining - who cares.
Brake parts cleaner is a good solvent. Use on a shop rag or towel to get the most out of it. Even WD-40 works OK to clean up accumulated sludge.
Don't be in a hurry. pray things down and give it some time to soak in.
After cleaning, be certain to lube everything well

Thanks very much for your response. What about a honing stone to smooth some of the mating surfaces (I.e., cross slide and ways)? My large has a somewhat rough surface in some places.

 

[extropic]

Thanks very much for your response. What about a honing stone to smooth some of the mating surfaces (I.e., cross slide and ways)? My large has a somewhat rough surface in some places.

Large? Is that a typo? Not sure I understand what you mean.

Regarding stones, you want to eliminate any high spots, but don't be concerned about any low spots. Think of the low spots as places for additional lubricating oil to accumulate. If there is so much wear or damage that the low areas are a problem, you have just graduated beyond of the minor refurbishment zone.

 

[markba633csi]

Brake kleen is strong, might take the paint off- I'd use something milder like thinner or Coleman fuel

 

[rabler]

On a lathe, precision contact surfaces (ways) rely on oil for smooth sliding action. It turns out that some surface texture helps hold an oil film to give the best action. Before you go attaching those surfaces, what is the cause of the issues you are seeing? Does it appear to be manufacturing issues, wear, or mechanical abuse like something being dropped on it? In most cases you are best off cleaning up any contaminants (rust, dirt) and not trying to modify the metal surface in any way. Typically stoning would only be useful is if something has been dropped or impacted the surface, in which case there can be a crater with a raised rim around it, and you would only want to remove the rim, not eliminate the depression.

Anything beyond that requires careful considerations of the geometry of the surfaces. There is an entire art/science of dealing with these surfaces, often called scraping. It is certainly possible to proceed DIY, but you need to look into all the appropriate considerations or you risk altering the geometry of the surfaces and reducing the accuracy of the lathe. That is the biggest danger of getting ambitious on cleaning up a lathe. That doesn't preclude some improvements in de-burring, etc, just a heads up on what to be aware of.

 

[Jim Azelton]

Large? Is that a typo? Not sure I understand what you mean.

Regarding stones, you want to eliminate any high spots, but don't be concerned about any low spots. Think of the low spots as places for additional lubricating oil to accumulate. If there is so much wear or damage that the low areas are a problem, you have just graduated beyond of the minor refurbishment zone.

Yes, “large” was a typo—apologies. I meant lathe and didn’t re-read before posting.
Thanks for the feedback regarding stoning the surfaces.

 

[Jim Azelton]

On a lathe, precision contact surfaces (ways) rely on oil for smooth sliding action. It turns out that some surface texture helps hold an oil film to give the best action. Before you go attaching those surfaces, what is the cause of the issues you are seeing? Does it appear to be manufacturing issues, wear, or mechanical abuse like something being dropped on it? In most cases you are best off cleaning up any contaminants (rust, dirt) and not trying to modify the metal surface in any way. Typically stoning would only be useful is if something has been dropped or impacted the surface, in which case there can be a crater with a raised rim around it, and you would only want to remove the rim, not eliminate the depression.

Anything beyond that requires careful considerations of the geometry of the surfaces. There is an entire art/science of dealing with these surfaces, often called scraping. It is certainly possible to proceed DIY, but you need to look into all the appropriate considerations or you risk altering the geometry of the surfaces and reducing the accuracy of the lathe. That is the biggest danger of getting ambitious on cleaning up a lathe. That doesn't preclude some improvements in de-burring, etc, just a heads up on what to be aware of.

Great info—thank you!
The areas I was referring to look to me like simply poor quality manufacturing, ie, visually “rough” surface (not “mirror” precise). I agree about the geometry aspect too—which was the basis for my hesitation of doing that.