Another Lurker with a Question

[Michael Barry]

I've been reading everyone's informative posts and looking at all the impressive pictures for a few months now. You folks turn out some beautiful stuff. I'd like to take advantage of your expertise to help me out with my current project.
My sister showed me a picture of a tall CD cabinet and asked me to make her one. It looked like a good challenge so I agreed. The cabinet has a round top, like a half circle. My plan is to cut 8 2-1/2 in wide boards beveled at 11-1/4 degrees and glue them up. Then plane and sand the top round and smooth. I think I'll cut them on the table saw but I'm not sure the little cheap angle gauge I bought will be very acccurate. Is there any way to cut the bevels accurately without spend a pile of money on a high priced gauge?
Thanks.

[Ken Fitzgerald]

Michael, I'm having a hard time envisioning what you're try to do but........if you've registered you're not a LURKER anymore! :eek: :rolleyes: :p Welcome! :D I'm sure somebody with more insight than I will come up with an answer for your question! Again.......Welcome!

[Todd Burch]

Don't cut bevels (unless you want to)!

Let's say that you'll be using 1/2" thick material for the top. Cut hollows and rounds. One one edge of your board, cut a 1/4" radius bead cut. On the mating board, cut a 1/4" radius cove cut. Now, you have a round-socket, of sorts, that you can set at any angle and glue in place. Here's a picture. You could use a router with 1/4" radius bits (1 cove and 1 roundover) for the entire operation.

[Michael Barry]

The top of the cabinet is like is like a half cylinder. I was gonna make it kinda like a coopered top.

[Michael Barry]

Todd, Your method looks like it's worth a try. How would you glue the pieces up? In a form?

[Todd Burch]

Yes, a form would work. Or, you could glue/nail it in place, as you went, to your gables.

If you wanted to get REAL fancy, you could cove out the bottom of the segments on your tablesaw so that the inside of the dome would be smoother. (We're going to have to dub you our honorary Cooper!)

[Jamie Buxton]

Don't cut bevels (unless you want to)!

Let's say that you'll be using 1/2" thick material for the top. Cut hollows and rounds. One one edge of your board, cut a 1/4" radius bead cut. On the mating board, cut a 1/4" radius cove cut. Now, you have a round-socket, of sorts, that you can set at any angle and glue in place. Here's a picture. You could use a router with 1/4" radius bits (1 cove and 1 roundover) for the entire operation.

Todd ---
Hunh?? I don't think that will work. The tips of the socket will run into the sides of the mating board at any angle other than straight.
Jamie

[Chris Padilla]

The Fluting and Beading Bits Todd is referring to should work but it depends on the radius of the workpiece you want to make and how wide each board is to be. In fact, the width of the board you use is key to getting the correct radius regardless of what method/bit you choose. The flute/bead bits will be designed for a specific thickness of board...usually 1/4". Also, you need two bits for this system.

Here are two more choices for router bits:

(1) Chamfer Router Bit These come in varying angles with a bearing to cut the angles you need. I've seen 11.25, 15, 22.5, 25, 30, and 45 degree tapers. Only 1 bit here and wood thickness is limited by the length of the cutting blade on the bit.

(2) Birdsmouth Bit or Mutli-Sided Glue Joint Bit These are kinda cool and they give more glue surface than the chamfer or flute/bead bits. Again, only 1 bit required here and another benefit is you only need cut one side of the board...the other stays square. This bit cuts an angled "L-shape" into the board and the board thickness is limited by the length of the cutting edge. Neat things with this bit is a ribbed look on the outside as opposed to smooth if you want it. Check out Eagle America (www.eagle-america.com (http://www.eagle-america.com)) or MLCS (www.mlcswoodworking.com (http://www.mlcswoodworking.com)) to see these bits. They can be a bit harder to locate as they aren't as common. This bit would be my choice, I think.

[Chris Padilla]

Todd ---
Hunh?? I don't think that will work. The tips of the socket will run into the sides of the mating board at any angle other than straight.
Jamie
Jamie,

It will work fine...canoes and hot tubs are often made this way. It is the width of the board that matters as to how tight/large a radius curve you want to make. True, you will be limited as to how much of an angle the two boards can make but this works fine.

The only issue I see with this method is the need for two bits and the wood thickness...all 3 need to be matched up.

[Todd Burch]

Jamie, as I drew it with precision, with a true, full 1/4" radius on both pieces, you are right. In practice though, the whole arc would be moved closer to the edge, therefore the cove would not be as deep, and the bead not as deep either, thus allowing more swing.

[Michael Barry]

After further consideration I went ahead and cut bevels in some scrap oak to see if the Gauge-it would work. I cut some slots in the edges of the boards and used splines keep them lined up. The curvature of the top looked pretty good during the dry fit. It's all clamped up right now. I think I got lucky and those scraps may just turn out to be the top of the cabinet. Thanks for your help guys, the cove and radius method will probably come in handy for an umbrella stand I've got planned. It rains alot down here y'know.

[Jamie Buxton]

Jamie, as I drew it with precision, with a true, full 1/4" radius on both pieces, you are right. In practice though, the whole arc would be moved closer to the edge, therefore the cove would not be as deep, and the bead not as deep either, thus allowing more swing.

Todd ---
So the two boards look kinda like a rule joint? If so, I don't understand the advantage. When they're bent to 22 degrees, the inside face will have a discontinuity, and the outside face will have a gap, no? In contrast, simple straight bevels offer no gaps or discontinuity, and can be cut easily on a table saw. Heck, if you have access to a jointer, the bevel can be cleaned up there for a really tight joint.

Jamie