Boo Yew RD

[Selfbowman]

Smik what is as the arrow weight you shot from the 55# bow in the force draw?   Arvin

[bownarra]

great work again DC - i once had some glueing problems when did a "belly lam over the handle"...glueing onto the "front side" of wood makes weaker glue joint imho. watch out, my last r/d also was 191fps 

No not at all.
If you prep everything right and execute it all correctly gluing the belly lam up the riser ramp is by far the best way to go. It is a much more complicated procedure than just gluing a chunk onto the belly of the handle area...but it is bombproof.
There is a reason virtually every glass bow is made this way and it isn't because it is weaker!

DC to get yourself closer, here are a few things to try.
More deflex built into the riser. (reference Adam Karpowzi's d/r bows) Reflex the whole limb, tiny bit inner limb, increasing as you progress along the limb towards the recurve. Make your bows tri-lams (walnut or similar core) and use a two step glue0up with as much perry as you dare. Also trap your bow so it is about 3/4 the width of the limb,e especially inner/mid limb, fade out the trapping a little towards the tips. Use as thick but narrow a recurve as you dare, I've gone narrower than I though possible before....doesn't make for the sturdiest bow out there but good enough. You can also splice in stiff wood recurves. Or go the laminated route, these are super strong and can be reduced further than a regular tip, the gluelines add virtually no weight. No heat used either so the wood is still at full strength.....
Good luck.

[simk]

DC:

You got 191 with a 26" draw?

Yes, it's a little while now and I decided better not to post about it   
Arvin:

Smik what is as the arrow weight you shot from the 55# bow in the force draw?

This is the fdc from another bow that blew up when I took it to 28" for fdc (glueing problem) (pic 1). I never checked fps on this particular one as it was too heavy for me to shoot consistently. The 191fps was a 358gn arrow at 36# @ 26" on another bow, same profile (pic 2). Same profile on a third bow got me 186fps @ 33# with 330gn arrow @26" - this bow has different, less aggressive, tiller. Tillered a little more to an arc (no pic).

bownarra: could be - I had my problems and a friend of mine - a timber construction engineer - told my the endgrain thing.

[willie]

The 191fps was a 358gn arrow at 36# @ 26" on another bow, same profile (pic 2). Same profile on a third bow got me 186fps @ 33# with 330gn arrow @26" - this bow has different, less aggressive, tiller. Tillered a little more to an arc (no pic).

Simk, do you have any pics of the unstrung profiles?
thanks.

[simk]

willie:...the lower one...

[DC]

That extra 2" would make quite a difference. You should make your own machine. It wasn't a big job.

[DC]

DC to get yourself closer, here are a few things to try.
More deflex built into the riser. (reference Adam Karpowzi's d/r bows) Reflex the whole limb, tiny bit inner limb, increasing as you progress along the limb towards the recurve. Make your bows tri-lams (walnut or similar core) and use a two step glue0up with as much perry as you dare. Also trap your bow so it is about 3/4 the width of the limb,e especially inner/mid limb, fade out the trapping a little towards the tips. Use as thick but narrow a recurve as you dare, I've gone narrower than I though possible before....doesn't make for the sturdiest bow out there but good enough. You can also splice in stiff wood recurves. Or go the laminated route, these are super strong and can be reduced further than a regular tip, the gluelines add virtually no weight. No heat used either so the wood is still at full strength.....
Good luck.

What would be the advantage of a tri lam? Is it just the lighter limb or does the slightly different grain direction do something. I've been trying to avoid the complication of another layer although on the bows I've had to rescue with a belly lam I seem the get a few fast bows.
 I've thought about trapping but the limbs are so thin(approx .375") that I didn't think it would buy much. I also thought that the belly edge radius would get awful sharp. If you used the old radius of a pea for the corners there's nothing left of your trapping.
 If I were to use a laminated recurve should I just "V" joint it on. Is it necessary to run the backing right up the recurve or could I stop it at the splice? Due to an elderly moment I seem to have a nice pair of bamboo backing strips that are about 2" short.
Thanks for the hints

[DC]

Speaking of gluing things, I heat treated both sides the belly strips quite aggressively. They are dark brown/light black. I was just wondering if that would affect the glue joint? I've already glued the belly strips to the riser so that ship has sailed but I still have to glue the backing on. Any cautions I should take?

[mmattockx]

If you prep everything right and execute it all correctly gluing the belly lam up the riser ramp is by far the best way to go. It is a much more complicated procedure than just gluing a chunk onto the belly of the handle area...but it is bombproof.

Exactly. The glue joint doesn't have to be as strong because the stresses ride up the belly lam over the handle instead of following the glue line under the handle and popping it loose.

Or go the laminated route, these are super strong and can be reduced further than a regular tip, the gluelines add virtually no weight.

Do you have a preferred or recommended wood for laminating into tip recurves?

bownarra: could be - I had my problems and a friend of mine - a timber construction engineer - told my the endgrain thing.

Your friend is correct that endgrain glue joints are weaker. This is overcome by the fact that running the belly lam up the fades is a far better way to transition into a stiff handle than gluing the handle onto the belly surface. You get a somewhat weaker glue joint, but a much lower stress concentration at the fade.

I also thought that the belly edge radius would get awful sharp. If you used the old radius of a pea for the corners there's nothing left of your trapping.

The belly side doesn't really need much of a radius at all. Even on the back the radius of a pea guideline is way more than necessary. I have been radiusing the back corners about 0.080" and on the belly I just break the sharp corner with a couple swipes of a sanding block with 120 grit paper.

If I were to use a laminated recurve should I just "V" joint it on. Is it necessary to run the backing right up the recurve or could I stop it at the splice?

Should be no different than siyahs, should it not? I would run the backing over the tip of the V on the splice, but it doesn't offer much help beyond the splice if the laminated piece is made stiff enough on its own.


Mark

[DC]

I would run the backing over the tip of the V on the splice,


Mark

Now there's a thought. As long as I can remember it. Thanks

[DC]

More deflex built into the riser. (reference Adam Karpowzi's d/r bows)

Is this in his Horn Bow book? Where might I look?

[bownarra]

MMattockx has answered the questions well Thanks
The tri-lam route lets you build in a prestressed eg perry reflex glue-up. Do the glue-up in two stages. Belly and core, then add the backing. It is more messing about but that is what you will have to do to get the 200fps. You've re--awakened my interest in it too haha, I haven't built any bows like I describe for a while now b ut maybe I will
You can have a spliced in recurve with nothing 'protecting' the splice - no problem. I've done it many times and yes a simple v-splice.
Why heat treat both sides of the belly lams?

[DC]

I was trying to get the heat treat as deep and even as I could. I'm not positive but I think I've scraped though the heat treat a few times.

[bownarra]

Another reason for the tri-lam approach is that it isn't too hard to get your recipe and stack info dialled in.....so tillering is only a bit of tweaking to get to full draw and take account of any funny bits of wood:) Leaving you with a full heat treated belly.
Do you have a drum sander for lam prepping?

[DC]

Another reason for the tri-lam approach is that it isn't too hard to get your recipe and stack info dialled in.....so tillering is only a bit of tweaking to get to full draw and take account of any funny bits of wood:) Leaving you with a full heat treated belly.
Do you have a drum sander for lam prepping?

That is a couple of the reasons I'm shying away from tri lams. Keeping detailed records and pretty much building the same bow over and over are not really my thing even though my boo yews are pretty similar to each other. We'll see.
 I have a cobbled up thickness sander I assembled on my metal lathe. The drum is one of those compressed rubber things that is a bit out of round and a bit concave. I could turn a solid drum I guess.