Marble Ball?

[Gregg Vaughn]

I came across several 6" diameter marble balls, marked down to $3 at Hobby Lobby. They range from dark gray to black and are mostly without veins (I guess these were considered not as desireable as the veined balls by the decorating public.)

I'm contemplating what to do with them ... has anyone worked with one of these yet? It would seem that the engraveable area would be fairly small unless you can figure out a way to rotate the ball on the rotorary attachment.

I'm new and this project is too advanced for me ... I hate to ruin any of them, they would be pretty if the kinks can be worked out.

[Jerry Allen]

Cut or turn some rings to fit your rotary. A 3 or 4 inch plastic plumbing cap or section of pipe might might be useful double sided taped or glued to a flat wheel.
Your lens has approx. 1/4" focus depth. That means you could easily engrave within a 2.4" (and even a little larger) band at the center of the ball.
Choosing and planning a design that takes that into account makes sense. You could also rotate the ball after the first pass, or make naroow bands without rotating to the left and right sides of the midlle band. The steeper it gets, the narower they must be. I.e., the first band to the left and right would have to be about .45" and the next pair about .32".

[Gary Hair]

If it were me, I would laser a mask and sand carve them. That way you can laser whatever you like and the mask is flat while you laser it.

Kinda hard to do if you don't have sandcarving equipment though...

Gary