Author Topic: bamboo backed and bellied hickory bow  (Read 1343 times)

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Offline superdav95

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Re: bamboo backed and bellied hickory bow
« Reply #15 on: June 01, 2024, 09:59:35 am »
Tandy leather has some 6 count linen that would require about 10 strands on that design. It seems like a rope but it works.

Iíve got some number 35 3 cord flax linen from Barbour.  Iíve been trying to get it to hold in my tensioner rig for stretching string without breaking.   I wonder if my Flemish twist are too tight perhaps and the linen is cutting itself or wearing on itself being abrasive when twisted.   Iíll keep testing this out and post a pic of one when it survives.  I canít find the string you speak of here.  The site I went to shows li en but doesnít give info on thread count. 
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Offline superdav95

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Re: bamboo backed and bellied hickory bow
« Reply #16 on: June 01, 2024, 10:22:01 am »
Amazing bow; great job.

What draw weight were you chasing when tillering it prior to putting the belly lam on?

Thanks Aussie!   Ya great question actually.  For these I tillered them to about 20Ē draw to about 30-35lbs prior to belly lam glue up.  Make the belly lam thinner then you think.  Also taper them out towards the tips.  I also thinned down the ramp area for the fades for better glue up.  The belly boo strip adds a lot of draw weight!  You can see my glue lines at the fades could be better actually but was not too concerned as it was not bending there.   
« Last Edit: June 01, 2024, 10:40:28 am by superdav95 »
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Offline superdav95

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Re: bamboo backed and bellied hickory bow
« Reply #17 on: June 01, 2024, 10:37:04 am »
Cool bow Dave  - and very well made of course! Whenever I see one of those Boo-backed/and-bellied bows I got rememeberd to my personal bucket list. Still a few glue-up problems to solve for me. Bamboo belly should be awesome I imagine. cheers

Thanks Simon!  Iíve only had two of these survive mind you but I suspect that the issue with the one that blew up was more about week spot at a node on the backing lamination that was the cause.  I had done the same process but again only out to 20Ē draw.  This failure didnít present itself until approaching full draw.  I noticed a hinge developing getting out to about 26Ē  I initially thought it was bad glue up but upon examining further it was clear that the boo was weak at the node just down from where the hinge was happening.   Anyway I should have taken some pics to document better but ended up in my burn pile with the rest of my failures.  Lol.  I would consider doing a tutorial or build along once I get a few more of these under my belt.  Still testing these really.  So far Iíve put about 150 through this latest build and it has settled in nicely.  The first one I did that survived last year I have reduced the draw weight to 50lbs.  I did this by filing down the inner nodes on belly like this latest one.  Seemed to have worked.  Put a few more shots through it and all seems good.   Iím gonna leave this one now and hopefully get it to the flats for distance shoot.  Fingers crossed.   The belly slat is important to get thin at the fades area in order to get good glue up where the ramp fade is.  Iíve tried heating up and pre bending these with some success too but find that there is a risk of splitting due to it being so thin.  Thickness of the strings are just under .095Ē. The bending part of limb is about .120-.125Ē tapering down to .090-.095Ē out at the tip ends.  I measure this carefully for both lams to get the same prior to glue up.  I keep these bows narrow and it helps with maintaining consistency due to the crown of bamboo slats.  I get choosy on my boo slats to pick the flattest sections I can to avoid excessive crown.  I also heat treat my blood lams when they are about 1/8Ē thick and then thin them from there and put in tapers.  Boo takes very well to heat treatment as far as increased resistance and performance and mass.  Anyway Iím rambling here.  Thanks for looking. 
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Offline simk

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Re: bamboo backed and bellied hickory bow
« Reply #18 on: June 01, 2024, 01:01:28 pm »
Dave. You have my respect making these so reflexed and so fast and pretty heavy. However my guts say its too much performance and not so much durability - at least me myself I couldn't make those last long and not overly loosing the reflex. When you have that much initial string tension the whole system to me seems very vulnerable even to minor things and if you have one little weak spot that is not going to be stable but increase. And you always have a weak spot. It's really on the edge. But yeah, if you wanna go to the flats you need to...good luck, hope to read about. Me myself and I are content with a little less performance meanwhile, just tryin' to make a very good bow - stopped chasing speed...really (-; almost (-; sometimes stll taking my chrono measurments, but when making a bow its not the primary goal.
« Last Edit: June 01, 2024, 01:04:54 pm by simk »
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Offline superdav95

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Re: bamboo backed and bellied hickory bow
« Reply #19 on: June 01, 2024, 02:37:19 pm »
Dave. You have my respect making these so reflexed and so fast and pretty heavy. However my guts say its too much performance and not so much durability - at least me myself I couldn't make those last long and not overly loosing the reflex. When you have that much initial string tension the whole system to me seems very vulnerable even to minor things and if you have one little weak spot that is not going to be stable but increase. And you always have a weak spot. It's really on the edge. But yeah, if you wanna go to the flats you need to...good luck, hope to read about. Me myself and I are content with a little less performance meanwhile, just tryin' to make a very good bow - stopped chasing speed...really (-; almost (-; sometimes stll taking my chrono measurments, but when making a bow its not the primary goal.


Thankyou.  Very true indeed.  Itís in the edge of failure.  Iím hoping they do t blow up on me but half expecting them to.  I hear that makes a decent flight bow though.  We shall see.  Fingers crossed 🤞
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Offline Selfbowman

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Re: bamboo backed and bellied hickory bow
« Reply #20 on: June 01, 2024, 04:14:32 pm »
Iíve built that design for some years . If the bow is tillered good it just takes set. If built these bows for 6-8 IBO shooters that are still shooting the bows. They draw smooth, are fast and reliable. But yes  they will only break records for a certain amount of time. The design has won many IBO world championships. So donít knock it till you tried it. Dave is better at it than me so I expect some of Arvinís records to go down. I am excited to see his interests in the sport. I will continue to help him and others to shoot for distance. If itís not your cup of tea I understand. I donít play video games.🤠🤠
Well I'll say!!  Osage is king!!

Offline Will B

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Re: bamboo backed and bellied hickory bow
« Reply #21 on: June 01, 2024, 06:37:56 pm »
Great bow, Dave. I liked the videos. Impressive speed. Very nice work as always.

Offline mmattockx

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Re: bamboo backed and bellied hickory bow
« Reply #22 on: June 01, 2024, 06:56:33 pm »
I started out with about 4.5" after glue up of the belly lams.  I had pretillered this bow out to 20" after assembling the boo backing lan to the hickory core. 

Beautiful bow, Dave. A couple questions:

1) Did you pre-bend the back lam and/or core lam before gluing them up with the 4.5" of reflex?
2) It's hard to tell from the pics, but it looks like you flattened the belly lam completely, removing all the crown, nodes, etc. Is that correct?


Mark

Offline superdav95

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Re: bamboo backed and bellied hickory bow
« Reply #23 on: June 01, 2024, 11:28:44 pm »
Iíve built that design for some years . If the bow is tillered good it just takes set. If built these bows for 6-8 IBO shooters that are still shooting the bows. They draw smooth, are fast and reliable. But yes  they will only break records for a certain amount of time. The design has won many IBO world championships. So donít knock it till you tried it. Dave is better at it than me so I expect some of Arvinís records to go down. I am excited to see his interests in the sport. I will continue to help him and others to shoot for distance. If itís not your cup of tea I understand. I donít play video games.🤠🤠

Thanks Arvin!  I doubt Iím better then you.  I may get lucky with your help.   Gotta figure out a proper string now and some flight arrows. 
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Offline superdav95

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Re: bamboo backed and bellied hickory bow
« Reply #24 on: June 01, 2024, 11:29:35 pm »
Great bow, Dave. I liked the videos. Impressive speed. Very nice work as always.

Thanks Will.  Much appreciated
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Offline superdav95

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Re: bamboo backed and bellied hickory bow
« Reply #25 on: June 01, 2024, 11:37:41 pm »
I started out with about 4.5" after glue up of the belly lams.  I had pretillered this bow out to 20" after assembling the boo backing lan to the hickory core. 

Beautiful bow, Dave. A couple questions:

1) Did you pre-bend the back lam and/or core lam before gluing them up with the 4.5" of reflex?
2) It's hard to tell from the pics, but it looks like you flattened the belly lam completely, removing all the crown, nodes, etc. Is that correct?


Mark

1.  I did not pre bend the back laminations.  I just heat treated them to drive out some moisture and harden it a bit.  I then taper after that out towards the ends. 

2.  I did not flatten the belly lams I only filed down the nodes a bit.  The natural crown of the strip was retained. 
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Offline mmattockx

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Re: bamboo backed and bellied hickory bow
« Reply #26 on: June 02, 2024, 01:41:24 pm »
1.  I did not pre bend the back laminations.  I just heat treated them to drive out some moisture and harden it a bit.  I then taper after that out towards the ends.

In that case, what does your form look like for that glue up?


Mark

Offline superdav95

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Re: bamboo backed and bellied hickory bow
« Reply #27 on: June 02, 2024, 03:44:56 pm »
1.  I did not pre bend the back laminations.  I just heat treated them to drive out some moisture and harden it a bit.  I then taper after that out towards the ends.

In that case, what does your form look like for that glue up?


Mark

Mark,   Here is a link to a video I did a while back showing similar set up for belly lam glue up.  This particular one shows a horn belly lam but you get the concept.  Itís pretty much the same.  I tried to find some pics but they are buried somewhere.  Lol.  Pictured here is a set up for my back lamination using bike tubes as many have done.  I add in the amount of reflex I want with clamps to the table.  Itís very important to make sure everything is straight after wrapping with the tubing as it has the tendency to introduce twist and misaligned tips.  The forms I used in this were ideal for horn but could also be used equally well for boo lams.  The only real challenge may be the crown on the belly lams but this can be worked around to get good results. 


https://www.dropbox.com/scl/fi/zdl6ek505rlo19rs3rypy/IMG_3386.MOV?rlkey=m9p5wvow806c4q63bipzzd512&dl=0


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Offline superdav95

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Re: bamboo backed and bellied hickory bow
« Reply #28 on: June 02, 2024, 04:07:57 pm »
side view


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Offline Selfbowman

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Re: bamboo backed and bellied hickory bow
« Reply #29 on: June 03, 2024, 11:04:49 am »
Maybe someone from England can  suggests some good linen for our flight bows.
Well I'll say!!  Osage is king!!