laser level for line on curved surface?

I could probably rig up a pencil-type method by setting up blocks on each side of the upside down bowl with a straight edge across. (Picture bowl upside down in doorway just big enough for it to fit through.) Then I could use the straight edge as a guide for a pencil. Of course it depends then on my being able to hold the pencil exactly plumb, and on finding a way to extend its length long enough to reach to the bottom edge.

We're not talking big size here (for now at least) - bowl diameter maybe

8.5", height probably 4 to 4.5". If I could suspend a laser level on the horizontal bar over the upside down bowl, seems as if I could get a line across the whole surface to follow with a pencil or other marker. I think they make some levels with magnetic bases, just like ordinary torpedo levels. So if the horizontal bar were steel, I could suspend it that way.

Of course the level would have to be able to do a 90 degree line and not just point straight ahead, but I think they make them so they do.

Harbor Freight sells a laser level that emits both a spot and a horizontal fan beam. It's about $12. I've used mine to mark cut lines on

55 gal oil drums (for a Department BBQ grill :). One of our Geology instructors used it to demonstrate elevation contour lines on models of land formations. Also, a visiting sculpture in the Arts Department is looking at it to transfer layouts from paper or models to stone.

Stupid spell checkers! I need a "what I meant checker"!

Alrighty then, In my mind I see that we started this exercise with cutting a sphere in 1/2 to get the bowl, now you want to cut the bowl in 1/2 again to get a 1/4 sphere. Instead of turning the bowl upside down, turn it so that it is flat up against a verticle surface (wall?) then use your height guage (on the floor) again to mark across the middle and you have two 1/4 spheres.

or perhaps make a slice so that one part

Ok here you have to not have the bowl verticle, but at some angle that gives the resultant peices you want. If you want to make your bowl into a 1/3 and

2/3 sections then tilt the bowl up at 60 degrees ( 180degrees/3) and make your mark. The height of the marker will be set at a point on the rim of the bowl that intersects a line drawn on the bowl that is across the diameter and parallel to the floor. This assumes that you want a pie shaped cut, as you would cut a mellon for breakfast.

If you want to cut at a right angle to the rim of the bowl then leave the bowl verticle and set the height guage at whatever proportion of the height you want to section the bowl at.

I need the cut to be as

Hmm. Prudence dictates, but I don't think this what the OP was asking about. I could be wrong.

Jim

Possibly. In my crude setup, distinct diffraction lines were visible on the squares next to the slit. The brightness of the line was significantly reduced, but it was still quite visible (much better than in the photo). The apparent width of the line before the slit was about

3/16". That after was approximately equal to the slit width: just a tad more than 1/32" over the two or three foot distance that I checked.

Jim

what about sticking it on/in a lathe? or something that would spin it, then just touch it with something to make a line. (I think you are trying to mark a line for cutting of a sphere, not sure if i'm right)