Question about blended nocks

[4est Trekker]

For what it's worth, I'll offer my thoughts on the subject.  If you look at how wood is violated along a growth ring, you'll find that it's often the porous early growth that fails.  (Likewise, dimensional lumber often tears out when the early growth ring fails.)  The string is, in general, trying to slip down the limbs (less so the shorter the bow is).  If you're not careful (and lucky) in your design and execution, that force could cause the string to sheer the "natural overlay" that you've created right off.  Best care scenario is that you could just sand the area down and add an overlay.  Worst case scenario is that it tears out and ruins the bow.

You could improve your design by adding deeper grooves on the SIDES of the tips, which would transfer more of the load perpendicular to the grain.  Relying primarily on a groove on the back of the bow (whether as you've done it or on with an overlay) localizes the strain along the weakest orientation.

I prefer glued-on overlays because a properly prepared and glued joint will be STRONGER than the wood around it (quite the opposite of the "joint" that the early growth rings function as).   

Perhaps that makes sense?   

[huisme]

You're right, the first one I did I didn't go deep enough into the last late growth ring and the early wood started to lift. I've been careful since to make sure the string is off of the  early wood enough that it doesn't leave an impression after shooting. It's very easy with my thicker ringed stuff, but for the nocks you see it required a lot of fine tuning.

I've just had the right mix of good and bad experiences to feel safe with these nocks. I don't try these with small rings, and I still do overlays if I fail to shape the blended nock properly, but once it's shaped properly I still haven't seen that these are less safe than overlays. Glue should be stronger, but these have proven to be at least as strong as necessary.

It makes sens,e and it's what I think about while making these. I'll be careful and keep testing rigorously

[mikekeswick]

For what it's worth, I'll offer my thoughts on the subject.  If you look at how wood is violated along a growth ring, you'll find that it's often the porous early growth that fails.  (Likewise, dimensional lumber often tears out when the early growth ring fails.)  The string is, in general, trying to slip down the limbs (less so the shorter the bow is).  If you're not careful (and lucky) in your design and execution, that force could cause the string to sheer the "natural overlay" that you've created right off.  Best care scenario is that you could just sand the area down and add an overlay.  Worst case scenario is that it tears out and ruins the bow.

You could improve your design by adding deeper grooves on the SIDES of the tips, which would transfer more of the load perpendicular to the grain.  Relying primarily on a groove on the back of the bow (whether as you've done it or on with an overlay) localizes the strain along the weakest orientation.

I prefer glued-on overlays because a properly prepared and glued joint will be STRONGER than the wood around it (quite the opposite of the "joint" that the early growth rings function as).   

Perhaps that makes sense? 

My advice too   

[Marc St Louis]

For what it's worth, I'll offer my thoughts on the subject.  If you look at how wood is violated along a growth ring, you'll find that it's often the porous early growth that fails.  (Likewise, dimensional lumber often tears out when the early growth ring fails.)  The string is, in general, trying to slip down the limbs (less so the shorter the bow is).  If you're not careful (and lucky) in your design and execution, that force could cause the string to sheer the "natural overlay" that you've created right off.  Best care scenario is that you could just sand the area down and add an overlay.  Worst case scenario is that it tears out and ruins the bow.

You could improve your design by adding deeper grooves on the SIDES of the tips, which would transfer more of the load perpendicular to the grain.  Relying primarily on a groove on the back of the bow (whether as you've done it or on with an overlay) localizes the strain along the weakest orientation.

I prefer glued-on overlays because a properly prepared and glued joint will be STRONGER than the wood around it (quite the opposite of the "joint" that the early growth rings function as).   

Perhaps that makes sense? 

Actually it's the brace height that determines how much shear pressure on the nocks, this depends a bit on the bow's design.  The lower the brace height the more shear force on the nock. 

What you have there is perfectly suitable for a longbow/flatbow with sufficient brace height.  I wouldn't trust it on an R/D bow or a Recurve

[huisme]

What you have there is perfectly suitable for a longbow/flatbow with sufficient brace height.  I wouldn't trust it on an R/D bow or a Recurve.

I tried it on a recurve once. Lets just say I learned that the hard way

[PatM]

A good insurance policy for nocks like that is to cut a slot and glue in a spline to shore up the area. Check out this Homer Prouty yew bow featuring that technique.
 The link was removed because it was from an auction site that is not a PA sponsor. You should be able to quickly find the pics by googling for Prouty Yew bows.