On the longbow I am building for m son, I was wondering where (in reference to the centerline of the riser) I should cut the shelf and window?? I would assume it needs to be a few inches (more or less) above the measured centerline of the riser but just exactly where for optimal performance I don't know.

Anybody??

1 1/4" to 2" above center IMHO

I like 1 1/4" above center to keep the shelf close to my bow hand.

I put it 1 1/8". Measure from the center of the web of your hand(pressure point on the grip with a straight wrist) to the place you would like the arrow to be. I like it close.

1" - 1 1/4"

Rgk, I have an Internation Viper longbow that the shelf is 2 1/8 above center. Seems strange to me, but it shoots where I look so it must be OK. Good luck with your sons bow.

I think the closer to the hand/center line would be the best.  Papa Bear used to modify his shelf so that arrow would sit on his knuckle.  I heard he was a pretty successful hunter   :D   That being said, it's really up to each individuals preferance.  Tim

From 1 to 1.5 inches above center line.  I cut mine so that the high point is 1.25" above.

Tim, don't mistake your hand for the center line.  two diffent things here.
ChuckC

Don't mean to hijack this thread but a related question....

Wouldn't you want the center line of the bow to be in the throat or shallowest part of the grip?

Good point chuck, I guess it all depends on the design of the bow.

Madness, I was under the impression that the center line was/is/usually at the shallow part of the grip, but again, its all up to the bowyer and what he feels is the best setup for his particular bow.

I always try to get my arrow as close to the center as I can.  On my recurves I do as Madness suggested and make the throat of grip. I am able to make the shelf between 1" and 1 1/4" above the center.  I shoot with my hand relatively open and with most of the presure on that point so it works well for me and for most people who shoot them.  
I don't have nearly as much experience with longbows, but most shelves seem to be a bit higher than recurves. Mine seem to be between
1 1/2" and 1 3/4". I think that it is because many longbow shooters shoot with a lower wrist and heal the bow putting presure a bit lower on the grip.  
It also seems to me that the further you get the shelf from the center of the bow, the more important the difference in tiller between the top and bottom limb becomes.

Brad

Thanks all, I will go with 1 1/2 above the centerline.