Made a sphere

[Bill Kahn]

Following Stefan’s youtube video

I made a copper sphere and a brass sphere. (Well, sort of spheres. I am not at all sure how to measure how close to a sphere some random lumpy shape is, but these random lumpy shapes roll pretty nicely on my granite plate. But also, not near as nicely as a ball bearing does.)

Given copper is anitmicrobial, and that small balls are fun to roll around and just have in one’s pocket, and the times suggest antimicrobial about now is particularly useful, I combined the three ideas. I can pretend they are not just pretty, but useful.

-Bill

 

[eugene13]

Like Captain Queeg (Humphrey Bogart) in the movie "Caine Mutiny"?

 

[benmychree]

I don't think I'd count on them for protection from COVID

 

[Winegrower]

They LOOK pretty dang spherical. And nice finish!

 

[Bill Kahn]

Here are some annotated snapshots of the sphere steps. I tried to visualize what Stephan tried to explain. But even after working out the boring bar sweep diameter, cylinder diameter and length, and the tilt angle, and carefully watching the cylinder become a sphere .01” at a time, I still don’t feel like I actually understand it. Three dimensional geometry is hard. -Bill

 

[bakrch]

'sphery nice.

 

[Lo-Fi]

Really fun, isn't it! I tried my hand at it too, made some missing balls for handles on my bridgeport after watching that video of Stefan's.

How did you manage such a lovely finish?

 

[Bill Kahn]

...

How did you manage such a lovely finish?

Oh. I like yours—it is useful, not just decorative. (Even if I do like to believe my copper will ward off evil spirits.)

Finish is just sandpaper. Mount on the lathe and start at 220 to get the machining lines off. Then work through every grade. 320, 400, 600, 800, 1000, 1200, 1500, 2000, 2500, 3000, 5000 was my sequence. It is just 20 seconds at each grade. 600 RPM. And it gets pretty nice. As I roll my balls on the floor (fascinating learning that the floors of a fairly new house turn out are not actually level) I will not bother with any polishing sequence. If you do try to polish, by holding by hand on a buffing wheel, heads up. A fraction of a second inattention and the ball slips out and hits the concrete floor and, well, so much for a nice finish. Yeah, ask me how I know. I love how we all just post the stuff that worked out on this forum. I had 4 earlier (I call “study pieces”) failures before getting something to work adequately. To get the creation navel “sphere-ized” and polished up took some fiddling. I may make another and snap some photos to show how I did. Nothing I am proud of. Not elegant. But worked. -Bill

 

[tjb]

I may make another and snap some photos to show how I did.

Would love to see that. I'm sure I'm not alone.

Regards,
Terry

 

[Lo-Fi]

Oh. I like yours—it is useful, not just decorative. (Even if I do like to believe my copper will ward off evil spirits.)

Finish is just sandpaper.

Nicely done, and thanks I left mine with the machine finish as I quite like the swirly pattern.

I've got some video, I'll post up if it's any good.