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Main Boards => The Bowyer's Bench => Topic started by: oldandslow on May 08, 2021, 07:40:59 AM
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What is the purpose of the taper when laminating?
Does a carbon fiber lamination reduce limb thickness back to belly for a given weight?
Does stabilcore work?
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I'll get the first one anyway...
The taper is in there to make the bow bend properly. without it you will be weak at end of fades and hinge most likely.
On narrower bows you use more total taper because you have less taper on limb edges.
Each bow design may use different taper rate due to limb design.
For the other 2 ?s I haven't used carbon as the gain isn't worth the money to me. Not a speed hunter..
But it's reported you need to reduce stack.
Stabilcore works to give some torsional stability, I proved this to myself with the recurve I just built with the monster hooks on it. First one off the form a couple years back without it blew up first pull. This one is doing great with it under glass back and belly , except I don't like it... :laughing:
Edit, I don't like the bow, the S-core is fine...
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Stabil-kore is awesome, yes it works ;)
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Thank you gents. Much appreciated.
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Take two pieces of lam, one tapered the other parralel and clamp them to the edge of the bench. Bend both at the same time from the tips and see how they bend, Keep going until one of them breaks and see which goes first. Your probably already know the answer. :)
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That was a very good answer long :thumbsup:
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parralel?
I'm still trying to fugger out what that is:)
:laughing:
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Agreed on a short fade that dont have a long thin taper tapered lams are easier on it. But if you build the fade or wedge that can work some you will be okay.
I believe in stablecore (would be better with a 45 % lay up tho.
Carbon works too many $$ for me.
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Agreed on a short fade that dont have a long thin taper tapered lams are easier on it. But if you build the fade or wedge that can work some you will be okay.
I believe in stablecore (would be better with a 45 % lay up tho.
Carbon works too many $$ for me.
I do not understand 45% lay up
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45/45° Fiber orientation, i guess.
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45/45° Fiber orientation, i guess.
Lol. What does that mean?
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45/45° Fiber orientation, i guess.
Lol. What does that mean?
Looks like this. https://compositeenvisions.com/commercial-grade-carbon-fiber-fabric-plain-weave-3k-5-7oz-193gsm-with-web-lock-stabilization/
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45/45° Fiber orientation, i guess.
Lol. What does that mean?
The fibers in a Standard Glass Laminate are all in the Same Direktion.
0°
The fibers in Stabilcore are halt linear and half crosswise.
0°/90° that gives a little bit torsional stability.
If you want maximal torsional stability, the fibers should be 45°/45°
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Righto! Got it.
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Kenny, you said "On narrower bows you use less total taper because you have less taper on limb edges."
Did you mean to say, 'On narrower bows you use (more) total taper because you have less taper on limb edges.' ?
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OOPS yes sorry! Glad you caught that misinformation. Fixed it thanks!
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OOPS yes sorry! Glad you caught that misinformation.
Someone gotta keep an eye on ya ole timer:)
:wavey: :laughing:
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I'm surprised you didn't catch it Pops! :biglaugh:
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I don't make gwass bows:)
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45 like the carbon is cut. I expect the carbon is laid up in sheets and cut at that angle. That will have some waste.
The stable core prolly laid up in long rolls.
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What is the purpose of the taper when laminating?
Kenny gave you the short answer, but here is a slightly longer version.
Depending on the back profile of the bow limbs the limbs will need to taper in thickness from the riser to the tips to achieve a smooth bend when drawn. Wood bowyers spend a lot of time on this because they are working with a much less forgiving medium and need the whole limb to bend properly to have a functional bow that lasts. Fibreglass is so much stronger and tougher that you can have a very non-optimal taper and still get a useful bow out of it. Wood breaks or takes massive set if you don't get it right.
Mark
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What is the purpose of the taper when laminating?
Kenny gave you the short answer, but here is a slightly longer version.
Depending on the back profile of the bow limbs the limbs will need to taper in thickness from the riser to the tips to achieve a smooth bend when drawn. Wood bowyers spend a lot of time on this because they are working with a much less forgiving medium and need the whole limb to bend properly to have a functional bow that lasts. Fibreglass is so much stronger and tougher that you can have a very non-optimal taper and still get a useful bow out of it. Wood breaks or takes massive set if you don't get it right.
Mark
Good 'splain.
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Wood breaks or takes massive set if you don't get it right.
Yes it does:)
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Wood breaks or takes massive set if you don't get it right.
Yes it does:)
Voice of sperience? LOL :wavey:
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Yupper....
:wavey:
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I reckon if you a knothead you know pretty much about wood :laughing: :laughing:
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:biglaugh:
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This is the way I see it. Getting the proper bend in the limb is also achieved by tapering the limb width from the fades out to the tips. Limb width tapering isn't just for looks. Try to imagine what the limb bend would look like if the width was parallel for its entire length. You don't want to get the limbs too narrow either especially on a flat thin recurve limb because you lose stability. So to achieve the proper bend without losing stability the thickness is also tapered. Proper limb bend is achieved with a balance of width and thickness taper. Depending on what you want the limb bend to look like you may be able to achieve it with no thickness taper using parallel lams, or a power lam, or reversing the taper with the thick butt end of the lam at the limb tip or a combination of these but normally the thickness taper decreases toward the tip.
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This is the way I see it. Getting the proper bend in the limb is also achieved by tapering the limb width from the fades out to the tips. Limb width tapering isn't just for looks. Try to imagine what the limb bend would look like if the width was parallel for its entire length. You don't want to get the limbs too narrow either especially on a flat thin recurve limb because you lose stability. So to achieve the proper bend without losing stability the thickness is also tapered. Proper limb bend is achieved with a balance of width and thickness taper. Depending on what you want the limb bend to look like you may be able to achieve it with no thickness taper using parallel lams, or a power lam, or reversing the taper with the thick butt end of the lam at the limb tip or a combination of these but normally the thickness taper decreases toward the tip.
Yep, and there's the fun part. Somewhat expensive , but fun... :thumbsup:
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Plenty of bows have been build with untapered lams and they work. Thats not to say it's a good design, they don't have any hand shock or they are pleasant to shoot. But if you want to slap something together and you don't have a way to taper, you can still make a bow with them
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Proper limb bend is achieved with a balance of width and thickness taper.
+1. Both the width and thickness tapers work together and need to be correctly matched to get the bend right.
Plenty of bows have been build with untapered lams and they work. Thats not to say it's a good design, they don't have any hand shock or they are pleasant to shoot. But if you want to slap something together and you don't have a way to taper, you can still make a bow with them
For sure. If you go with a pyramid width taper you need no thickness taper to get it bending well. Fibreglass offers much more range on the width/thickness combinations that will work because you can concentrate the bend in a small part of limb and it will survive that with no issues. Wood cannot typically stand that much concentrated strain and needs the entire limb bending properly to work. The process of tillering a wood bow is really matching the thickness taper to the back profile to end up with a nice, smooth bend.
Mark
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Wood cannot typically stand that much concentrated strain and needs the entire limb bending properly to work. The process of tillering a wood bow is really matching the thickness taper to the back profile to end up with a nice, smooth bend.
Yupper and it takes some time.
And thickness tapering my core lam, boo backing and tapering the width profile from 1.25 at the flares to .5 at the tips makes the tillering process easier.
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Rody!! You using decimals now ?? :goldtooth:
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Had too cause you skipped class the day they wanted to learnt ya fractions:)
:laughing: