Bending Plywood

[steven sherman]

I have a piece of plywood 1/2 " thick 12" w x 36" L , I need to create an arc with a height of 3" over the length of the 36 ". The radius of the bend is 55.5"

I was going to cut kerfs in the plywood and create the bend. Are there guidelines for the depth of the cut, width of kerf and distance between the kerfs that might make this a bit easier than trial and error.

Thanks for your help

Steve

[Butch Edwards]

I have a piece of plywood 1/2 " thick 12" w x 36" L , I need to create an arc with a height of 3" over the length of the 36 ". The radius of the bend is 55.5"

I was going to cut kerfs in the plywood and create the bend. Are there guidelines for the depth of the cut, width of kerf and distance between the kerfs that might make this a bit easier than trial and error.

Thanks for your help

Steve

Steve, I had to do the same thing when I made a half-round hall table. The plans called for making a step-jig, and to cut thru the ply leaving the last 2 plys... it worked out great....

[Bill Arnold]

I found this article (http://www.woodworkingspecialops.com/page2.htm) that provides some of the math involved.

[Steve Rozmiarek]

Why not forget the kerfs, and just use bending ply? Assuming you are veneering...

I've seen porly executed kerfs telegraph pretty bad on bent ply, which does not look good. Butch's advice on leaving the last two plys is good, but you can still end up with obvious facets if you are bending much of an arc.

Personally if I where doing what you are thinking of, I'd get bending ply, or at least laminate two or three thinner sheets of ply to eliminate the kerfs. Thats just me though, and it really depends on what you are building if it is worth the trouble or not.