Bamboo Backed Ipe R/D Longbow [with Video]

[bowhunter15]

I picked up a B-50 Dacron string at the shop. It stretched out quite a bit putting it on, as the guy behind the counter estimated it was probably still an 80lb bow based on stringing it. I've put some more twists in it to get the brace height back. Right now I have roughly 55 full twists and it's brace height is 4.5". Is it safe to say I need a 1" shorter string?

[Roy from Pa]

A shorter string and more wood removed from the bow before stringing it again. A 50 pound bow will do all you want, and be easier to shoot...

[bowhunter15]

Will do. Also, I read on Sam Harper's BBI build-a-long that he sanded off the "rind" on the bamboo backing, starting with a pneumatic drum sander and working down to 1000 grit sandpaper. Should I sand the shiny bamboo surface as well?

[Roy from Pa]

I wouldn't bother with that yet. That can be done when the bow is done being tillered. Don't use a sander either. Use a scraper then 220 - 320 paper sanding by hand lengthwise along the limbs. You just want to barely remove the rine.

[Bowjunkie]

And it's better to leave a wee bit of it on there, in any tiny furrows, than to scrape or sand enough to get it all out/off, compromising power fibers in the 'ridges' in the process.

I would never use any type of power sander on the back(outside) surface of the bamboo. It's certainly not a difficult or time consuming thing to do by hand.

I do most of the removal of the rind with a scraper, with any sanding literally taking just a minute or two.

[bowhunter15]

Okay, update time. I've taken a little more off, go the bow braced to a closer to realistic 7 to 7 1/8", and have exercised it back to 23". It's still 57# at this point so I have a ways to go, but how is my progress? Bottom limb (right) is bending a bit more than the top, which seams wrong, but the pulley is still coming straight down. It's more pronounced at brace and the limbs are closer at 23". Perhaps that's all just part of the dynamic timing. Keep removing wood evenly?

 

Also, there's a tiny amount of twist in the lower limb, near the tip. You can see how it's at a little bit of an angle. Should I even worry about it?

 

[fujimo]

roys got some cool diagrammes, that he will post shortly- thad'll help with the twist- seems like you have still got lotsa room to deal with it!
lookin cookin!

[Zradix]

I stole this from Roy waaay back..
 

[bowhunter15]

When I hit 24" draw, the string slips out of the groove on the top limb, making a little plucking noise. The fulcrum is closer to the top limb tip than the bottom, so the angle is different, explaining why it jumps out of the top limb first. What's the best way to deal with this? Rasp the grooves in deeper? Try and cut new grooves adjacent to these in order to better represent the angle of pull at full draw? (I still have ~4" more to go before full draw). Something else?  

P.S. Everything else on the bow is going great. It looks very nice at this draw, and is getting closer to my desired draw weight.
   

   

   

[fujimo]

so this is how i like to do my tips, especially to deal with that problem!
 

[Roy from Pa]

One side of the limb that's twisting is most likely thinner than the other side. Check the thickness on both sides and compare them. The bow string will drift towards the thinner weaker side. So wood has to be removed from the side the string is moving away from. Also check the string grooves depth. Get the limb twist fixed first. Then continue tillering. After fixing the problem, the pull rope will probably drift off the line. Remove wood accordingly to get it tracking straight again.

I noticed in the pictures that the edges of the limbs look square, they need slightly rounded over and I also seen rasp marks along the sides of the limbs, those should be sanded smooth before pulling the bow on the tree. Having rasp scratches in the wood is asking for trouble when working the bow on the tree.

[bowhunter15]

Thanks guys. I'll get to work on those items tonight. Hopefully I'll have it ready for the first shots by the end of the weekend.

[fujimo]

looking good- yer doing a great job- its quite a bit tougher tillering those RD bows  

[LittleBen]

Looking good. Roy is right though, get that twisted sorted out before anything else. And round edges, always.

[bowhunter15]

@27". Comments, questions, concerns? Also I have it braced at 6.5" right now (length of my fist and extended thumb. I've seen numbers anywhere from 6.5 to 8 for R/D bows, and since I have that big humped style grip, I figured it will naturally like a little shorter measurement than a locator style or sculpted recurve style grip. Once I start shooting it more, I can surely fine tune it.

   

[takefive]

Tiller looks beautiful to me.  I brace mine just high enough so the string doesn't slap my wrist, about 6".  But that's just me.
Really nice work  

[bowhunter15]

Took it to a local archery shop. It was tough to buy only one arrow to try out (I have a dozen shafts, points, and a fletching jig, coming in the mail). They ended up finding a 2413 aluminum that was 29", so probably a good bit stiff. Here were my thoughts: It'll take a lot of getting used to a trad bow with no letoff, but I've got plenty of time to get use to it. It was well balanced, but my muscles still quivered a bit holding at full draw. Also, I had a little bit of string slap so I'll increase the BH a bit until it goes away. It seemed a bit noisy. Mostly the "twang" of the string. I'm assuming some bow hush will help. Also, since the aluminum arrow spine was stiff, I believe the rear end of the arrow was probably hitting the riser. It would have explained some of the noise, and my rest broke. The rubber prong on the bear weather style rest sheared clean off after about 10 shots. One feather was facing straight down.

I'm assuming the following:
1) Increasing the BH will eliminate wrist slap, reduce hand shock, and made the bow quieter.
2) Building my ~700 grain UEFOC arrows will make the bow quiter. Being spined correctly, they will not smash the riser, resulting in no more broken rubber rests and a quieter shot.
3) Adding bow hush near the limb tips will quiet the bow, assuming some of the noise is from string slap.
4) Adding a suede/leather grip cover will also help with hand shock.

My next steps for the bow are to continue sanding with finer and finer grit sandpaper, adding a suede/leather grip cover, replacing the rest, and probably apply a clear coat. Then build the arrows when they come in. I'm planning on building the arrows with the following materials according the to the Ashby reports:

-Full length Victory VForce HV 350
-Gold tip 100 grain brass inserts (might need to be polished down .001" inch to fit)
-300 grain field points, and eventually 300 grain single bevel broadheads with high MA
-4 white feathers fletched 90-90. Will start at 4" and reduce as allowed for good flight.
-Turbulator made from a thin strip of arrow wrap material.
-About 1.5" aluminum arrow segments used as external footing, increasing structural integrity behind that heavy tip and increasing the FOC (probably also stiffening dynamic spine a bit as well).

[takefive]

I agree that it's kind of a shock going from a wheel bow to a trad bow.  You'll be surprised how quickly you adapt to it, though, as long as you're not over bowed.  IMO, starting with a lighter bow and working your way to a heavier one is a good idea.
Wooden longbows are usually very quiet, sometimes whisper quiet.  Hope the correct spined arrows solve that noise problem.

[Zradix]

Curve looks pretty for sure.

To be honest though, it looks to me that the outter 60% of the limbs aren't bending basically at all.
Left side's hinge is centered about where the upper horizontal lines of the grid goes by.

Right side's is centered a touch farther down the limb..maybe 1/2 way between the upper and second grid line.

It might be the lighting but the right side looks to be bending a fair amount right at the fade.

I'm sorry to be so critical..but you asked for it...lol.

I'm not the best builder in the world..closer to the worst really..but that's what I see.

[bowhunter15]

I have no problem reducing the mids out to the tips if that's what needs to be done. Especially since, now that I look at it, there is still reflex near the tips. I've seen a lot of pictures of R/D that look more D shaped by the time they're at full draw. I agree the lighting does make it harder to tell. I should photoshop the shadows out.