Bowl with s-curved, sloping sides and grape leaves

[llwood]

Bowl with an s-curve in the sides that gets wider at the top.

[llwood]

If you'll indulge me, I'd like to share how I did this, because it took a while to figure out.

Got 3 copies of Dome-Dish 30 from the clip art.
Stretched them all out to be 300 inches so they looked like cylinders.
Took the center one and change the combine mode to subtract so it becomes a dish.
Arranged them so the 2 domes and one dish make a wave pattern, as shown in the screenshot.

[llwood]

I wanted to bowl to get wider toward the top, so I got Pyramid 0.75 from the 3D Tabs folder in clip art. I stretched it out both directions so that the peak of the pyramid was at the top of the bowl.

[llwood]

Combine the pyramid with the wave by changing the combine mode of the pyramid to Add.

[llwood]

Then overlay a 3D model of grape leaves with combine mode Add.
When wrapped, this results in the following preview.

[llwood]

Add some 2D toolpaths to roundover the top and bottom rims of the bowl.
The flat (not wrapped) preview looks like this.

[llwood]

Finally, save toolpaths with a postprocessor that wraps Y to A and cut on the turning center.
Then hollow out the interior on a drill press (to remove the majority of the material) and the remainder of the interior on the lathe.
This results in the bowls pictured above.

I know no-one asked how I did it, but I wanted to share anyway because I'm proud of it. Thanks for indulging me.

Andy

[highpockets]

Andy,

Thanks for sharing your latest bowl and how you achieved this beautiful piece.

You have every right to be proud!!!

I hope some day to get my 4th axis up and running and when I do you're on my list of people to contact

[bravesoul]

Andy,

I have been watching the beautiful work that you do and have just one question. I have put oak leaves on a straight sided bowl but have a line where the ends meet, what/how do you take care of that? I want to try something similar to your bowls (curved) but would like to figure out the this issue first. I don't have a pic that shows the issue but here is what I have done.

[llwood]

I have put oak leaves on a straight sided bowl but have a line where the ends meet, what/how do you take care of that? I want to try something similar to your bowls (curved) but would like to figure out the this issue first.

We've had a lot of frustration with this also. Because you can't preview the place where the ends come together, it becomes a matter of trial and error. If there's too little overlap, there is a ridge at the joint. If there's too much overlap, there is a groove. And a 3D pattern of this size takes hours to cut so it's quite time consuming to do trial and error.

In order to make the trial and error more efficient, I created a version that cut just the last inch on each side. This way, we could see how the ends come together and adjust, then do another run on the same piece in a different place. The attached preview is a test of the edge of the "Open Leaf Bowl" I posted earlier.

The closest we've come is to have the bounding box overlap the edge of the material 0.155 on each side. There is still a slight groove at the joint with this but it's only noticeable if you know what you're looking for. I wanted to keep trying to get it closer but Marty said "It'll sand out," so this is the overlap we have been using on all our bowls. What overlap are you using?

I hope this helps,
Andy

[bravesoul]

Andy,

I increased the bounding box but probably should have taken the design slightly past the box, i need to play with it some more. I'll post pics once I get around to doing another test. Going to take me awhile as I have some household projects I have put off way to long.

Joe

[llwood]

Joe, I made a mistake on my earlier post. I forgot to mention that in order to keep the tools completely inside the border, I was using a boundary offset of the tool radius. For the roughing toolpath, I use a 1/4" end mill, so the boundary offset is -0.125. For the finish toolpath, I use a 1/8" ball nose (straight, not tapered), so the boundary offset is -0.0625. I use the same boundary box for both roughing and finish toolpaths, and even though the boundary box extends 0.155" beyond the part, when you take into account the boundary offset, it's really only 0.03". This is the case when cutting 3D models, and I imagine it will vary somewhat based on the tool you're using.

But when I look at the picture you showed, it looks like a V-Carve toolpath (Am I seeing that right?). If this is the case, I don't think any overlap would be necessary because the cut is defined by the vectors, even if they fall off the material (in the 2D preview), rather than the 3D model.

Those dang "household projects" can really interfere with the wood carving!
Andy