Axle polishing

[JCovert]

Has anyone used 3m polishing paper? It looks like 8000 grit (.5 micron) is the finest they produce and I've seen posts stating 12000 is used. What are your thoughts on prep using these products?

 

[GravityX]

Are you referring to the light blue, light pink and white ones. I've used them, but I also polish higher with other products on occasion.

 

[pony express]

I haven't found a whole lot of speed after the 3000 grit. I've tried to 30,000 and even 60,000 without much speed difference. Now i'm going to 3,000 and then a metal polish as my final step. It makes things easier. On many of the axels available you have to start with sand paper to get rid of the macine marks, otherwise I don't use sand paper.

If you use sand paper, be sure to use same type of firm (but not steel) polishing block to get a unifrom surface. I don't use water with the paper. I use my final polish as the lubricant.
Good racing

 

[JCovert]

Thanks. I've stopped at 2500 before however I found a super cool 20x magnifying pen at harbor freight so I am going to examine a few different methods. Additionally I am curious how concerned I should be about reducing the diameter of the axle when sanding away imperfections. The race I'm in allows for stock parts only which are considerably smaller than the wheel bore already. Is it more important to maintain proper clearances between bore n axle or to remove surface imperfections that would impede the hydrodynamic properties when using oil?

 

[Guest]

What material is recommended as a backing for the sand paper? I'm leaning towards MDF over regular wood due to lack of grain and uniform firmness but I'm open to any suggestions.

As far as the comment about surface imperfections impeding the hydrodynamic properties of oil, I can see "outies" doing that but not the "innies". I was reading about different oils on a gun forum and one of the well respected resident Big Dogs had this to say about reasons to not over polish...

"The dry lube of a fine enough particle can actually fill in the microscopic imperfections in the metal surface allowing for a smoother flow of liquids thus reducing viscosity"

Sounds logical to me and like a lot less work.

 

[Guest]

Hey Eccentric,

I like the system that micro mesh employs. They use a flexible foam backing on the super fine stuff. This just makes sense to me but is based on no testing. DD uses just the sandpaper without a backing in the video.

I feel that with oil smoother will always win over slight imperfections.

Just my gut talking.

 

[Guest]

Laserman, all good points you bring up. That's the beauty of Johns axles- they're straight and round so sandpaper alone is the cats meow. Although I feel a backing is necessary for the axles I'm working up now for a Royal Ranger car, #5 slotted round head wood screws. They are tapered and about 0.005" larger in circumference at the intersection. When I groove it I end up with one side much larger!

In the past I polished up to 60k grit sandpaper followed by diamond polish, now it's 8000 grit and Brasso so even though it's a step back the finished result is still pretty smooth. This is what makes the PWD so fun, all the small details.

 

[Guest]

nice! can you post a photo of these axles?

60k. Jeez!

I am with you. it is hard to imagine much difference after 10k.

Brasso is awesome!

 

[Guest]

I highly doubt I could take a quality pic that would show the sheen. I did find a pic on the net of an axle polished with 60,000 grit that will give you an idea. I've been wrong before and I'm sure I'll be wrong again but I feel that an axle can be polished to a point of diminishing returns speed wise. Now if no lube was involved I would polish that axle to a mirror shine like my life depended on it- but with the usage of a lube the micro "innie" scratches seem like they could function as mini lube reservoirs.