Lamination thickness - Question

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Mett
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Joined: Fri Nov 28, 2014 2:37 pm
Location: Deeral, Cairns

Lamination thickness - Question

#1 Post by Mett » Sat Dec 13, 2014 10:35 pm

In my recent efforts to build my first bow I decided to go and visit Flatliner who was kind enough to lend a hand. It was suggested to me that I should do a lot more research about the thickness of my laminations and my core.
I was wondering if anyone could give me some help for a recommended lam thickness. The bow that I'm wanting to make is a 66" Deflex/Reflex longbow with 1.5 inch limb width with 40 thou glass on the back and 50 thou glass on the belly. My goal weight is approximately 45# @28"
Any tips and constructive criticism is more than welcome!

Thanks to Flatliner for being so helpful and welcoming.

Thank you
~Matt

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greybeard
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Re: Lamination thickness - Question

#2 Post by greybeard » Sun Dec 14, 2014 8:11 am

Hi Matt,

The following is from Bingham's;

How do I determine the thickness of my limbs?

“You can find the Bingham Bow Draw Weight Chart in this catalogue. For our recurves, the limb thickness is composed of 2 pieces of Bo-tuff, 1 parallel, and 1 taper (.002”). The total limb thickness is the sum of all four layers, the taper being measured at the butt end.

For our 1 piece longbows and our shallow t.d. longbow, the limb thickness is composed of 2 pieces of Bo-tuff, 3 parallels, and 1 taper (.002”). The total limb thickness is the sum of all six layers, the taper being measured at the butt end. For our pronounced t.d. longbow, the limb thickness is composed of 2 pieces of Bo-tuff, 1 regular taper (.002”), 1 parallel, and 1 reverse taper (.002”).

The reverse taper is simply a taper that is reversed so that the thin end of the taper is at the butt end of the limb. The total limb thickness is the sum of all five layers, the regular taper being measured at the butt end and the reverse taper being measured at the thin end. In the case of the t.d. bows, the wedge is never considered part of the limb thickness.

Additionally, please note that this chart is accurate for Bingham Bows and designs only.

We are happy to offer advice if you are using your own design, but we cannot guarantee an accurate limb thickness for different designs.”
Bow Draw Weight Chart.pdf
(240.87 KiB) Downloaded 155 times
To have a look at the bow styles I suggest you down load their catalogue;

http://www.binghamprojects.com/

I think most bowyers find out by trial and error.

All the best with your bow making.

Daryl.
"And you must not stick for a groat or twelvepence more than another man would give, if it be a good bow.
For a good bow twice paid for, is better than an ill bow once broken.
[Ascham]

“If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?” [Einstein]

I am old enough to make my own decisions....Just not young enough to remember what I decided!....

JoeLethbridge
Posts: 98
Joined: Wed Dec 07, 2011 4:11 pm
Location: Gordonvale, QLD

Re: Lamination thickness - Question

#3 Post by JoeLethbridge » Wed Jan 07, 2015 11:55 am

Hi Mett, I live in Gordonvale, and Rob is currently teaching me to build a 55#@28" Reflex deflex with a length of 64". The template of this bow was copied from a black widow bow. Rob and I are currently working on the bow form. Rob is a skilled craftsman, and you can certainly count on him for good advice.

Cheers Joe

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woodie
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Location: hunter valley, NSW

Re: Lamination thickness - Question

#4 Post by woodie » Wed Jan 07, 2015 5:07 pm

I made a 66" longbow 45#@28" with 0.050" glass back and belly 18" riser with 2 0.080" and 1 0.100" laminations.
If that helps.
Woodie
may your arrows fly straight and true and your limbs return.

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