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View Full Version : Curved Hood - how to figure the cutout?


Jim Underwood
12-13-2012, 4:45 PM
Say you need to make a curved joint in plywood for a curved hood cabinet. How do you figure the part cutout for that?

I could probably figure out the compound angles for an angled cabinet, but... how do you figure a compound curved joint?

Anyone have any clues?
John Coloccia
12-13-2012, 5:26 PM
Do you have a picture or a sketch?
Jim Underwood
12-13-2012, 5:35 PM
247836

Something like this. Not exactly, but you get the picture...
Mel Fulks
12-13-2012, 5:50 PM
A friend was given some kind of gizmo that was manufactured for making templates for big sheet metal round ducts and stuff. Not an antique but some decades old,can't remember what it was called. I think I would have to use a lot of cardboard and tape.
Mel Fulks
12-13-2012, 6:10 PM
Bend a big piece of cardboard or bending ply to the shape of one curve ,then use that old stair work trick .A beam compass with the center point made like a donut to slide on a pipe to allow it to follow the contour of the first piece.
Jim Underwood
12-13-2012, 9:57 PM
Trouble is, I want to figure it out so I can cut it on our CNC router...

I can figure out how to do it by hand, but I need to draw it in CAD, so that next time it's a piece of cake.
John Coloccia
12-13-2012, 10:06 PM
Trouble is, I want to figure it out so I can cut it on our CNC router...

I can figure out how to do it by hand, but I need to draw it in CAD, so that next time it's a piece of cake.

You need a better cad program that can "unroll" surfaces. Then it would be trivial. What are you using for a cad program? This is almost like a sheet metal thing.
Mel Fulks
12-13-2012, 10:13 PM
Modern problems. Before: This would be so much easier with CNC. After:It's hard to do on CNC.
John Coloccia
12-13-2012, 10:17 PM
Well, the "easy" way to do it on just about any cad program is to scan in the cardboard pattern, and then match it in the CAD program with a spline. You could do that with a freeware engraving program, actually.

But I see your point....trading one set of problems for another :)
Jim Underwood
12-13-2012, 11:28 PM
You need a better cad program that can "unroll" surfaces. Then it would be trivial. What are you using for a cad program? This is almost like a sheet metal thing.

I have access to RouterCim (AutoCAD bolt-on), AlphaCAM, and ArtCAM. I also have Cabinet Vision, which is of little help in this instance.