35 5/8 radius. Actually 35.641 but close enough.

"Dick Snyder" wrote in message
...
I'm not sure how to compute the bending radius. Maybe you can help me.
Here
is what I know. The curved top piece of the bookcase will span a width of
45". The highest point of the curve above a flat surface for a reference
point will be 8".

"Lew Hodgett" wrote in message
k.net...
Dick Snyder wrote:
My daughter has asked me to build a bookcase for her baby's
nursery. She saw
something on-line that she likes. It has a curved top. I think I
will build
the bookcase out of birch as it will be painted and I am thinking of
laminating 3 1/4" pieces of birch plywood to do the curved top.

snip

Make sure you use what is known as "bending plywood".

Around here, 1/4" "bending" poplar is readily available.

The amount of "springback" is a function of the lamination thickness and
the bending radius, so can't answer your question.

I'd use epoxy with a slow hardner.

It will give you good "open time" and provide a rock solid lamination.

Don't be in a hurry to take it out of the clamps.

Have fun.

Lew