On Sat, 16 Jul 2005 08:09:10 +0100, "Steve"
wrote:

I intend to make 3 curved rafters for a garden application. Each rafter
needs to be 7ft(L) x4inch(H) x 1-1/2inch(W) finished. The radius of the
curve will be 10ft.

Material will be 1/4 inch external grade ply laminated to make up the width,
glued and screwed over a former. How much "spring back" should I allow for?

I had Resourcinol in my head but a previous post suggests this is OTT for
this sort of application (probably mega expensive too), suggestions
welcome.

I can probably buy these, but then thats just another learning opportunity
lost.


Odds are, you've already done this, but I did this exact thing last
week, and just happened to spot the thread today. The contractor I
now work for does very high-end historical remodeling/renovation, and
we had to fabricate a new roof for a garage extension to match the
existing structure- which in this case meant curved rafters with a
curved hip. To get it in, we got a bunch of 2" x 12" douglas fir,
and cut the rafters to shape with a bandsaw on-site. The first rafter
was rough sawn and then shaped with a rasp until it fit the curve of
the existing soffit perfectly, and then the subsequent rafters were
cut and then attached to the first (master) rafter with a C-clamp and
sanded to match the master with a belt sander. To get the hip, we
rough cut a hip rafter, tacked it into place, and then ran a string
line across the regular rafters every 4" to get reference marks to use
for plotting the extended curve.

Looks really nice, and it may or may not help you, depending on how
quickly you've gone after this project. FWIW, there was no springback
involved, as the new roof was sheathed with 1" x 4" cedar planks
rather than plywood to match the original construction.