Untitled Gardening Project #16

[xiphmont]

The small discs are fully machined. The finished... thingies... will stay indoors and don't need to worry about abrasion resistance or heavy-duty durability. There's no need for plating, anodizing, or clearcoating the final finish.

Polishing can be done by hand or by vibratory tumbling. Hand polishing is 'faster' but labor intensive. Vibratory tumbling requires a long period of time, but almost no labor and minimal supervision.

The first polishing step runs the discs in 'green' [medium coarse] wet-media silicon carbide triangles at max setting for 24 hours. This deburs, removes all tooling marks, and intentionally rounds off the edges of the discs. Although 16 discs will fit in the hopper at once, they'll tend to 'stack up' in one big mass with no media between. For this reason, polish eight at a time, requiring 12 days total.

The original, directly tooled surface is shiny but fragile. The tiny grooves from turning and milling have sharp, thin edges that show scratches easily and collect dirt. The first polishing step transforms this into a smooth, dull matte surface devoid of tooling marks. It may not look like forward progress, but it's substantially smoother than the tooled surface, more durable, and closer to a mirror finish than it appears.

Comments

[coraline]

...if i ended up with some tooled aluminum objects (as i hope to fairly soon) would i be able to come over and borrow the use of the tumbler? :)

[xiphmont.livejournal.com]

Sure. It's going to be set up and running for at least another month yet. The hopper should be able to swallow anything up to about 2.5"x2.5"x10"

Do you want cut down and polish or just polish? Strictly speaking, the step above was abrasive cut-down, not polishing. A true polishing step doesn't intentionally grind off metal.

I'll be changing to the next finer grade media (or maybe straight to polish) in about two weeks for the next step. Going from one type of media to another about an hour to set up. If I can slip you part into the schedule I have running, that's easiest.

[xiphmont.livejournal.com]

I really wish there was a way of editing/correcting typos in comments :-( I never notice them until after I post.

[coraline]

ok -- this will be two pieces which will start with probably 1.25" diameter cylindrical stock, shorter than 10" so that's perfect.

i think i need to do just about exactly what you're doing -- i'm starting with aluminum stock and then running it on a lathe. i'll need to get rid of the same sorts of microgrooves you're talking about in some way, and this seemed like the right sort of setup...

but in the next month seems less likely since i'm travelling for the next two weeks :/ but i'll ping you if i ever get the damned objects tooled :}

[xiphmont.livejournal.com]

Oh, if you have them after all the parts I'm running are done, that's fine too. It's just more time consuming to keep switching media types back and forth to slip something different into the middle of a run. I only have one hopper (they're surprisingly expensive) so it has to be cleaned very carefully befre being filled with a different media type. If I had more than one I could just dedicate each one to a different grit size.