Sam - 11-28-2010 at 01:06 PM
Dear luthiers,
I'd like to know the right dimensions of Oud's back wood . I've got a 100 years old walnut tree and I'm willing to slice it into pieces, and It will
make good tonewood. 
somebody may help me with the right deminision please ? ( one piece of wood's deminsions not ribs )
an example : 75 cm x 20 cm x 1 cm
Thank you,
Sam 
Yaron Naor - 11-28-2010 at 01:51 PM
I suggest you to slice it to much bigger billets than 75x20x1cm
and let it dry slowly.
The wood will crack a bit and bend and after it will be dry enough you can cut it to smaller billets... when you avoid the cracks....
Good Luck
Yaron Naor
Sam - 11-28-2010 at 02:33 PM
Well, it's already dried and was cut 5 years ago during the winter season.
each luthier gives different deminisions .. but it seems that they all have agreed to the 75 cm length .
got any better ideas?
FastForward - 11-28-2010 at 06:09 PM
1cm for the thickness is too little. You need a minimum for 4cm if you want to have 21 ribs for you oud. If you are very careful, with 4cm you will
have 19 ribs but its not easy, also it depends on the depth of your back. But would strongly suggest keeping it to at least 4cm thickness.
With 1cm thickness, you will either have way too many small ribs. Or you have to slice the wood for ribs across the 1cm dimension which won't be
easy.
So from my perspective, an ok size would be 75x20x4cm
Sam - 11-29-2010 at 11:53 AM
FastForward,
That's exaclty what I thought, 1cm thickness is not enough.
Do you think 75x20x4 cm will be enough to build a whole Oud ? shall I cut another piece of wood for the neck and pegbox??
SamirCanada - 11-30-2010 at 04:39 AM
75 length is generally accepted.
For the "showing side" if possible the "quarter sawn" side of the ribs. between 2.5 to 5 cm. This depends on the amount of ribs you plan to make your
oud with. You have to measure the widest point of each rib then add some (at least 0.5cm) room for shaping the rib. So ideally you want at least 3, 4,
5 cm.
width, depends on the width of your blade, your cutting technique and the amount of cuts you plan on making. 20cm seems like plenty but you should
always make extra ribs. For use in purfling and in case some break and they do break :P
Also 20 cm might not be possible so make 2 of 10cm etc...
Sam - 11-30-2010 at 10:00 AM
Samir , Yes you are right, They do break especialy if you wanna make very thin ribs . like 2m or less weidth ..
Thanks everybody for your time and advice.
Sam.
FastForward - 11-30-2010 at 02:03 PM
Inexperience as well as defects in the wood can cause ribs to break. For my oud I had 30 ribs cut and used 21 for the oud. All other 9 ribs were
mostly broken. I think I have one left in tact.
I would suggest thinning the ribs to about 2.2mm before bending, it will make your life easier. I used 3mm in the beginning and that was too much,
then I went down to about 2.5 and that made things much easier. Still I rushed a few ribs and ended up breaking them.
Invest some time into making a good bender, even if costs a little bit more. Bending was somewhat of a pain, particularly matching the ribs. It is
also a source of a good amount of waste. Avoid a bender with a pipe that has a small diameter, I would say anything below (10cm diameter) is not good
if you want to use a pipe bender.