Treasure chest style toy box

[msadkin]

I'll thinking about building a treasure chest style toy box for my very soon to be born grandchild. I would like it to have a dome style top, but don't know how to figure the angle to rip the boards to make it fit the top of the chest. I plan to make the chest 36"Lx20"Dx18"H. These dimensions are not set in stone. Assuming the lid would be a arc about 8" at the highest point, how would I figure the angles on each ripped board.

Any help would be appreciated.

Thank you,

Mike

[Don Z.]

It would depend on how many stiles you chose to use. The easiest thing to do would be to draw it. From there, you could decide if you wanted the same angle on each stile, or if you wanted to vary it with the shape, etc.

[flairwoodworks]

I agree with what Don said. When laying out a coppered top, I first draw the shape I want the cross section to be in full scale. Then I can work directly from the drawing. By the way, I like to do drawings on MDF because it shows pencil lines well and is more durable than paper. A drafting program should be able to help you calculate the angles too, if you were so inclined. The angles will depend on the width of the piece you use to make the top from.

[PaulMarcel]

+1 to previous answers. A sliding T-bevel gauge will make it easier to get the angles off a scale drawing.

Here's something you might find useful... a free article from Popular Woodworking on making a pirate chest, Arrrrrr! It has a coopered lid so your parrot do-do rolls off to the side.

[petersb]

I was going to attempt to explain how to do it and when I started writing it out, I had to go get a piece of paper and draw it out. After I figured it out, I decided that it would be easier to tell you to draw it out, instead of me explaining it because, well... I can't explain it! I guess drawing it out full scale and determining how many pieces you want to form the top would be where I would start and then try tweeking the width and angle on each piece on your drawing until you get what you are looking for. Sorry, I don't have a quick solution to your question. I'm a woodworker, sort of, not a geometry expert.

[msadkin]

Thanks for the suggestions. I guess I'll try drawing out the top and first divide it in half and continue to divide each segment in half until I end up with the amount of slats I think look good. I'll measure the angles angles and try that. Since the actual size of the chest can vary a bit, I think making the top first, then matching the chest to it may be safer. Should be an interesting way to get some practice on my "new" old right tilt Grizzly. Thanks again.

[msadkin]

Paul-Marcel, I checked out the treasure chest link you posted and I sure wish I knew more about using Sketch-Up. It would be nice to change the dimensions to match what I want. I'm sure it's not too difficult if you know how to use the program, But I can't make it do anything I want. I'll have to take some time to learn it a some point.

[Vic]

The easiest way I know how to figure out angles on a coopered panel is to do as above and draw it out. First draw a straight line line and mark the width you plan on achieving. Using dividers, bisect that line with a 90* line that goes down the page to accommodate whatever radius you'd like.

Draw your arc with the compass point on the 90* line and the pencil crossing the two points of width. Now it's a simple matter of bisecting the arc with the compass to make however many staves you wish to incorporate. Then you can either do the math, or use a protractor. Here's a brief tutorial I found on bisecting.