Author Topic: Overbuilt?  (Read 4124 times)

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Offline Badger

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Re: Overbuilt?
« Reply #15 on: May 25, 2020, 10:19:59 pm »
 Having no set in your bow will trump hitting a projected mass. I have made quite a few bows at the same dimensions and weight you built yours to and find at my projected mass the set is minimal but the wood you use will also affect this. Even thought I tend to treat all woods about the same as far as mass goes some woods should actually come in lighter, osage and yew can safely come in a bit lighter while some of the oaks should be mad a bit heavier as they are not as elastic.

Offline simk

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Re: Overbuilt?
« Reply #16 on: May 26, 2020, 02:55:46 am »
Thanks Willie for the interesting pics and read (????)  8) The unstrung profile of that "shooting machine" sure would be interesting. My wood was harvested on March 24 2020. I think it was dry. Still curious if it will change/warp somehow with further seasoning...

Thanks Del fur those numbers...sounds like formula 1  ;D

Thanks for judging that tiller bownarra! Finallizing it I'll take a few scrapes....

Thanks Steve Badger for clarifications - that really helps me to classify your mass theory a bit better - so it's not valid completly regardless of wood species...thanks.

After shooting the bow now it lost some more reflex (and a little puondage). It's almost straight now, which also is where I was aiming at. In my interpretation it's only some more stretch in the backing. At my 26" draw I got steady 172fps @ 10gpp and 177 @ 9gpp which I consider fine, considering there's still a little excess mass at the unshaped tips. The bow served it's purpose and showed that the wood is worth trying more complicated bows out of it. I will leave it as it is and not pike. have a nice day  (-S

« Last Edit: May 26, 2020, 03:02:07 am by simk »
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Offline BowEd

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Re: Overbuilt?
« Reply #17 on: May 26, 2020, 03:46:36 am »
That's pretty respectable speed from that bow.Nice bow too.
From what I've found is that some woods can handle different profiled bellys better than others with flat backs that are nonbacked.Osage is one that can.Yew too.
BowEd
You got to stand for something or you'll fall for anything.
Ed

Offline simk

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Re: Overbuilt?
« Reply #18 on: May 26, 2020, 07:07:48 am »
thanks BowEd! I'm always using these ash-backings and got the impression that they are a bit stretchy and prone to take some set. In my wild imagination a boo backing would hold the profile much better and provide better performance? never used one...
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Offline DC

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Re: Overbuilt?
« Reply #19 on: May 26, 2020, 09:50:54 am »
thanks BowEd! I'm always using these ash-backings and got the impression that they are a bit stretchy and prone to take some set.
The way to tell is to the saw the backing off. It's a bit drastic but very interesting. Saw it just under the backing. If the Ash is stretching it will show deflex once it's cut off. If a backed bow has some set and you saw the back off, normally the belly piece will show a lot of set and the back will be the same as when you first glued it up. At least on the two bows I did. I've never used Ash though, just Boo and Maple

Offline willie

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Re: Overbuilt?
« Reply #20 on: May 26, 2020, 11:38:29 am »
 
Quote
At my 26" draw I got steady 172fps @ 10gpp and 177 @ 9gpp which I consider fine

quite respectable speeds actually, considering the compression woods other qualities, I think the belly would have taken more strain in a more aggressive design,  but it would not be as fast that way.

Please let us know if the bow recovers it's reflex.

Offline simk

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Re: Overbuilt?
« Reply #21 on: May 26, 2020, 01:47:24 pm »
willie: it just lost glued in, artificial reflex so that will not happen I think. its still straight and didnt even start taking set.  but for science I could string it for 3 days and then see if it relaxes to straight profile ;D It's not half as bad as DC's idea  ;D but I still dont really like the idea a lot.
DC: What have you found out about the differences between maple and boo? Isnt the maple more stretchy. Does it preserve glued in reflex the same?
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Offline DC

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Re: Overbuilt?
« Reply #22 on: May 26, 2020, 02:00:28 pm »
I didn't really see any difference that I noticed. I trust the Boo more because you can tell which way the grain is going with Boo. With the kiln dried store bought maple that I had I was never sure that I had the grain just so. I just use the Boo now.

Offline simk

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Re: Overbuilt?
« Reply #23 on: May 26, 2020, 02:13:10 pm »
Thanks DC. I dont have easy access to boo but one day will make a boo-copy one of my ash-backed ones to check that...With my d/r attempts I always loose 2/3 of reflex. Glueing in 2" of reflex on a flatbow and ending with little to zero? Is this normal?

willie: Its stringed. We'll look at it again tomorrow  ;D it looks like some reflex has returned since shooting yesterday. but that again is probably the backing fooling around.
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Offline DC

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Re: Overbuilt?
« Reply #24 on: May 26, 2020, 02:27:13 pm »
Thanks DC. I dont have easy access to boo but one day will make a boo-copy one of my ash-backed ones to check that...With my d/r attempts I always loose 2/3 of reflex. Glueing in 2" of reflex on a flatbow and ending with little to zero? Is this normal?


I think there is too much going on to make a solid statement. You have set, pullout and at the same time sometimes you gain reflex in the first half of the tillering. Add all these together and you have confusion. At least I do. In the first half you have pullout combined with reflex gain countering each other so things go slowly. As you get further into it the reflex gain seems to leave so now you have set and pullout added together. Things happen fast. Confuses the he!! out of me ;D

Offline willie

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Re: Overbuilt?
« Reply #25 on: May 26, 2020, 02:39:34 pm »
Quote
it just lost glued in, artificial reflex so that will not happen I think. its still straight and didnt even start taking set.  but for science I could string it for 3 days and then see if it relaxes to straight profile

Simk,
just give it some time to recover, the wood is funny that way.
my maple backed bow lost its glued in reflex tillering and shooting in, but a few months* rest and it looks like I just took it out of the gluing fixture.  Shooting it again makes it straight, but it eventually recovers.

**a few months for my bow because it is strained fairly hard I am thinking. I am going to try not working the wood so hard on my next one. This belly wood can be worked very hard. I have 42" birch backed  compression wood with a cable back above the birch that I pulled to 75# at 20".


russian pics and buildalong here also.
http://www.primitivearcher.com/smf/index.php/topic,68162.0.html


« Last Edit: May 26, 2020, 05:34:45 pm by willie »

Offline DC

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Re: Overbuilt?
« Reply #26 on: May 26, 2020, 02:45:12 pm »
Do I remember reading something about these compression Pine bows being made and used wet. I don't know how they would accomplish that when all they had was hide glue. Don't know, maybe I'm misremembering ;D

Offline willie

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Re: Overbuilt?
« Reply #27 on: May 26, 2020, 03:25:26 pm »
from what I have researched, they work in wetter envrionments. I cannot cite the report, but I recall one account of how the bows were lashed to trees outside in the winter to keep them from drying out too much and warping.
Did you try putting the branch bow your were having trouble with in a less dry place?

Offline DC

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Re: Overbuilt?
« Reply #28 on: May 26, 2020, 04:32:08 pm »

Did you try putting the branch bow your were having trouble with in a less dry place?

No but summer is coming and the humidity will go up. I looked at it about two weeks ago and the string alignment was way out. I swore at it a put it in the COS. A few days later I took another look and the string alignment was good. Could be RH. Pretty much has to be actually, nothing else changes in the COS ;D ;D

Offline Hamish

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Re: Overbuilt?
« Reply #29 on: May 26, 2020, 04:54:16 pm »
Willie, Awesome post about the Russian bowyer. Never heard of him before. Thank you.