I still need to make an actual jig to measure the bottom of bowls and hollow forms, in the meantime I used the laser from my hollowing system to temporarily locate the bottom of this hollow form. When I get around to building the actual jig it will be carefully setup to measure exactly at center height.
The laser point was carefully aligned with the end of the cutting tip. Where the laser falls on the outside of the piece should be where the inside bottom of the hollow form is. Assuming that the cutter is bottomed out and is on the center line (I'm holding in place with one hand and taking the photo with the other) it looks like I have about 3/8" left in the bottom. Just enough to finish it off and make a slight concave spot for it to sit on.
Next up was a sample for what I might want to do on a larger scale. I saw a photo of a similar piece during Christian Burchard's spheres demo at the 2011 Desert Woodturning Roundup.
Turning a near perfect sphere is much harder than I initially thought. I used Christian's technique and got pretty close but it's definitely not perfect but it was pretty close.
Can you guess how it was hollowed and how the groove was cut in the middle (or is it the other way around). Also how was it held during these operation(s). I'll reveal how I did it in a couple of days, after some guesses have been made.
Interesting. Seems like it would have been turned like a hollow form with thick walls and a thicker base, then carve the center section away.???
ReplyDeleteTry again. No carving, all turning.
ReplyDeleteAll I can think of is that you turned the sphere normally, then re chucked it off center to cut the groove. Once the groove was large enough you re chucked it at a 90 degree angle and then hollowed it using the widest part of the groove as the vessel opening.
ReplyDeleteTerry, Pretty darn close, It was turned between centers and then between wooden cups for the outside shape. The headstock cup was moved off center, shifting the whole ball off center and the groove was turned. Then a jam chuck was turned to hold the piece while the inside was hollowed out through the groove.
ReplyDelete