V splice tip gap

[Tom Dulaney]

http://1.bp.blogspot.com/_QlTAdivgTKY/Sm-aU6_4L5I/AAAAAAAAAiw/30v43qwTdbU/s1600-h/bow+join+detail.jpg

^ I notice v splices very frequently have gaps between the apex of the male piece and the female piece.


Is this acceptable or does there have to be contact between the tips of the joint? Particularly when the female piece consists of two or more pieces that been laminated vertically (in my case)?


The second picture I posted is of the pre-contact Tuktut Nogai bow from arctic Canada, so they didn't have saws to make the splice. I don't know how they made it but I suspect the female joint was made by drilling holes and then scraping it to a fishtail.

 More of that bow here:


http://elfshotgallery.blogspot.com/2009/07/tuktut-nogait-bow-makes-great-first.html?m=1

[bownarra]

I prefer to make them perfect with no gaps. I tend to use v splices on hornbow cores so perfect is the only way haha
Make the end of the male section around 1mm or the width of your saw blades kerf. Cut the female section, work the sides flat and the bottom of the cut perfect. Then shape the male to fit, not touching the female part again. If you make the widest part of the male section 0.5 - 1mm wider than the gap in the female you can make a push fit that doesn't even need clamping, it 'clamps' itself.

[Tom Dulaney]

Thank you. But what about v splices when the bending limbs are extremely deflexed?

Do you think you could have a tip gap in that case? It seems to me that if the bending limbs are deflexed, there is way less compression force on the v splice, and thus it wouldn't matter if the apex of the male piece contacted the female piece? Even on  a horn bow.

[PatM]

It will depend on what goes over or under the splice as well.  I believe Chinese  composites had a small gap to theoretically prevent splitting of the bamboo core.  In any event quite a few joints were less than perfect.

[Eric Krewson]

Like pat said, few splices are perfect, depending on how much I am say daydreaming at the bandsaw mine can be from perfect to needing shims glued in to fill the gaps.

I have cut a little filler piece and glued it in to close tip gaps a time or two but it probably wasn't necessary. I always glue on more wood on top of the splice to build up the handle. 

[Del the cat]

All of the above...
But it just dawned on me that a nice fix might be to drill a small hole down through the gap and plug with a wooden/boo skewer.
Fills the gap, looks tidy, doesn't have sharp corners as crack propagators.
Not that I ever have gaps myself <cough splutter>
Del
(Actually i usually flood 'em with thin CA and sawdust)

[monoloco]

As a noob wanting/needing to do some splices, I'd love to see setups used - jigs etc.  I've been through TBB etc. but this forum and the collective knowledge are always an incredible resource.

I hope that's not considred a hijack!

[Jim Davis]

All of the above...
But it just dawned on me that a nice fix might be to drill a small hole down through the gap and plug with a wooden/boo skewer.
Fills the gap, looks tidy, doesn't have sharp corners as crack propagators.
 ... .

Just to add another aspect that might not make any practical difference, wood (don't know about bamboo) is not as strong in compression across the grain as with it.  IJS

[PatM]

Drilling a hole and filling it with a plug is essentially creating  a pin knot dead center of the bending stress.  Do we like those in staves?

[dylanholderman]

I thought a V splice wasn’t supposed to bend unless there’s a backing over it anyway?

[Del the cat]

Drilling a hole and filling it with a plug is essentially creating  a pin knot dead center of the bending stress.  Do we like those in staves?

If it's no bigger diameter than the gap, I don't really see how it can be any worse.
Del

[Tom Dulaney]

It will depend on what goes over or under the splice as well.  I believe Chinese  composites had a small gap to theoretically prevent splitting of the bamboo core.  In any event quite a few joints were less than perfect.

I greatly appreciate your input.

I thought a V splice wasn’t supposed to bend unless there’s a backing over it anyway?

Yes, that's not what I meant, though. Imagine a bow where the lower limbs are severely deflexed and bending, but the upper limbs are rigid, like a Scythian bow. The lower limb forms a male joint and is spliced in to the upper limb. There'a no splice in the bending portion.









^Imagine if the splice was located on this bow approximately where the fletching on the arrows is.



I don't see how it would matter if there was a gap at the tip of the splice, because it seems to me the forces acting on the v splice would be mainly tensile in nature.

In a bow like this the force is trying to pull the female upper limb off of the male upper limb. It's not like bows where the bending portions are straight or reflexed, where you will definitely have considerable compression forces acting directly upward on the splice, causing movement if there's a gap. Or at least, that's what my imperfect and intuitive mind is telling me.

Thanks to everyone else for your contributions to the discussionm

[PatM]

I wouldn't really use a Scythian bow for reference.  The whole bow is peppered with splices but it has sinew backing and sinew wrapping holding everything together.
 

[Tom Dulaney]

I wouldn't really use a Scythian bow for reference.  The whole bow is peppered with splices but it has sinew backing and sinew wrapping holding everything together.

Of course. I forgot to add that this is assuming the bow will be backed with sinew and wrapped with it as well.





^ those are severely defelexed lower limbs. Even stringing the bow shouldn't put much transverse pressure on the splice. Or so I think.

[Digital Caveman]

One of the limbs doesn't bend?  That sounds and looks like one of the craziest bow designs I've ever seen.  I'd love to know how it came about.