Backed Flatbow Siyahs

[Prarie Bowyer]

Pat,

where are the pics of the finished backed flat bows?  I thought I saw them a while ago.

[Wooden Spring]

Here's a thought...  If you cross pinned the siyah in place with, say, hickory dowels, would you still have to sinew wrap the joint?

[Onebowonder]

Here's a thought...  If you cross pinned the siyah in place with, say, hickory dowels, would you still have to sinew wrap the joint?

I've wondered about this many times - but I've come to think about it differently than I first did.  I think a large part of the strength of the wrapped joints comes from the glued surface area involved.  The the amount of glue holding surface area on a length of thread or sinew wrapping is very very high when compared to the very limited surface area of the pegs run thru the joint.  The crush-resistance and shear-resistance strength of the pegs themselves is very little engaged in this application.  ...or at least I've deluded myself into thinking that these excuses explain the physics involved better. 

BTW - Your 'crude drawings' are anything but!  I save them regularly to work with...

OneBow

[PatM]

 There wouldn't be enough thickness to support all but the thinnest of pins. Wrapping is a far better solution.

[Springbuck]

Here's a thought...  If you cross pinned the siyah in place with, say, hickory dowels, would you still have to sinew wrap the joint?

You'd have to thicken it substantially.  I'm with OneBow.  Modern glues are actually stronger than the wood, so the magic is in getting a nicely fitted glue joint.  The wrapping is there to help out, and keep it together if a ghlue joint fails, as well as making it look nice.

BTW, I just remembered that I have spliced a recurve onto a core, and then backed that with hickory or bamboo.

[PatM]

 Splicing into the core and then running the backing up the splice is the best option but that works better when just gluing in a typical recurved piece.

[Wooden Spring]

Rats... I was really hoping that pinning it would work. I had ideas of making the splice REALLY decorative, like the dragon's tail shown below. I can do wonders with a bandsaw, and I'd love to give that a go!

[PatM]

You're not thinking what you are doing with the grain of your outer limb.... I would keep your decoration to surface adornments rather than structural.
 
 

[Wooden Spring]

You're not thinking what you are doing with the grain of your outer limb.... I would keep your decoration to surface adornments rather than structural.
 
 

No doubt you're right. I'm just weird like that.   

[Springbuck]

You're not thinking what you are doing with the grain of your outer limb.... I would keep your decoration to surface adornments rather than structural.
 

 I agree with him.

 See, I think this would be POSSIBLE but the whole area, all the way down a couple inches below the splice at least would have to not bend AT ALL, costing you a huge amount of working limb length.  Same principle we tell new guys when they glue a handle on a board bow.  That handle can not bend, or it will pop off.  You can get away with murder if it is really stiff, but any flex will have that lifting splinters, etc....  When you splice two woods with different stiffnesses, their different resistance to flexing cna cause failure, too (one wants to flex a bit, and the other doesn't).

Use your skills to make a fancy overlay for the front and back of the siyah, or something.  You could even do the belly splice with the backing over the whole deal like that.  I made some belly splices with a finger-joiner on a router once that were pretty cool, but a lot of set up and planning.

[Wooden Spring]

10-4, no decorative attempt in the mating joint.

So, I think two more questions and I'll be ready to give it a go.
1) How do they affect the overal length of the bow, assuming a 28" draw? (my normal flat bows are 68" ntn)
> Should I keep the bow the same length to start with, and essentially stick the siyah on the end? Then gradually start making shorter bows?
2) Since I don't have easy access to sinew, could I wrap the joint in cotton cord soaked in Titebond 3?

[PatM]

Again that will depend on your choice of wood and width of limb/siyah length.  I  prefer about 60"-64" for this type of bow when using a strong belly wood. You're really just making a mollie with the levers set back a bit.
 Linen is the best natural choice for wrapping. Preferable to sinew in fact.

[Wooden Spring]

Linen? Awesome, that's easy since my wife is a seamstress.
Thanks dude!

[Onebowonder]

Silk is good, ...and is readily available, ...and has a bit of tradition to it, if that sort of thing matters to you.

OneBow

[willie]

Pat

spring buck asked eariler

Pat:  How is that elm backing made?  Did you actually slice the top layer off a log, leaving the back just like a self bow back, or is it from a board

?


and I have been hoping you might comment, as you usually seem quite generous sharing your methods

willie