Pretty Good Axle Prep
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- Apprentice
- Posts: 7
- Joined: Wed Feb 21, 2024 8:39 pm
- Location: Midlothian, VA
Pretty Good Axle Prep
Every year we run several workshops to help the scouts build fast cars and the longest and hardest step is the axle prep as it requires multiple rounds of sanding. I'm thinking of simplifying the step next year and wanted to hear from others on the thought process. Given that the nail is nickel plated (does anyone know by how much?) which is a very soft material, I'm not sure running through the various grits is really necessary. Meaning if a higher grit quickly sands through scratches then there is no need to run through the process of using each grit and with the courser grits you run the risk of the scouts eating too much of the axle away. I plan on taking some pictures of some different tests and posting them for everyone to see but it seems that going straight to 3000 wet sanding is enough to remove all of the scratches before moving on to a polishing compound, I've compared two axles under the microscope, one going from 400 - 800 - 1000 - 1500 - 2000 - 3000 then Mag polish to an axle that only used 3000 then mag polish and they appeared to have similar surface contaminations, but the diameter was slightly larger for the latter. Anyway, thought I'd run this through the hive mind to see if I'm missing something by just looking at the surface through the microscope.
Re: Pretty Good Axle Prep
For a build shop why don't you let them decide to stop based on their preference explaining that they can thin the axle down too much if they work too aggressive, part of learning the process?
I'm not going to say it's as good as going further and using more steps, but a lot can be said for some jeweler file work on the burs followed by a simple light 400 or 600 grit wet sand followed by some buffing using a car finish rubbing compound, and that might be all many of the kids have the patience for or feel is good enough...
I'm not going to say it's as good as going further and using more steps, but a lot can be said for some jeweler file work on the burs followed by a simple light 400 or 600 grit wet sand followed by some buffing using a car finish rubbing compound, and that might be all many of the kids have the patience for or feel is good enough...
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- Apprentice
- Posts: 7
- Joined: Wed Feb 21, 2024 8:39 pm
- Location: Midlothian, VA
Re: Pretty Good Axle Prep
I wish my microscope could take digital pictures, what I found was that sanding with 400 and 600 grit left very noticeable scratches in the nickel plating. We did some test axles by stepping through a finishing process and inspecting the axle under a microscope each time and it wasn't until we got to about 1000 grit and higher that we saw diminishing returns but the most surprising find was that we were able to wet sand with just 3000 grit to get the same result. I'm looking into a cheap way to grab some macro photos of this to share with everyone. I should also clarify this is just for the shaft, we noticed that the axle head itself was inconsistent in our limited tests, I think that is because we don't have a great way to apply even perpendicular pressure (We've used popsicle sticks, stir sticks, etc but no luck yet on getting consistent results. I've ordered some sanding stones that are square that may yield better results.