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Screw holes are not radially symmetric (run-out tolerance is too high)
Proposed Solutions:
Get inside circular (using cylinder hone)
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Order cylinder hone online
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Replace stones with 80 grit sandpaper.
Look at homemade turning tool
Research industry solutions
Ask around about any bigger lathes on campus
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Max Height: 8 feetz
Big Cylinder:
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https://www.keyence.com/ss/products/measure-sys/gd-and-t/type/run-out-tolerance.jsp
https://www.gdandtbasics.com/circularity/
Information:
Runout tolerance = Axis offset + Total circularity
(a.k.a. how much it wobbles and how far from a perfect circle it is)
Proposed solution online: Straight surface + diameter gauge?
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Gameplan:
Circularize interior using an engine hone
- Attaches to a drill and rotates three spring loaded grindstones that remove more or less material based on their spring pressure.
Circularize exterior using an improvised lathe
- Attach cylinder to a motor after the interior has been circularized (friction fit with laser cut wood circle?)
- Attach other end to a bearing so it can rotate (also friction fit with laser cut wood circle?)
- Fix a piece of sandpaper at a set diameter and move it up and down the cylinder until the entire thing matches that diameter (check tolerance at multiple locations to reduce error).
Backup method: Use a centerless grinder (more work but potentially better results)
- Cylinder sits on a rest while a grinder is rotated next to it
- A second regulating wheel is moved in to apply pressure and rotates without slipping with the cylinder
[As seen on Wikipedia ^]