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Main Boards => The Bowyer's Bench => Topic started by: rockkiller on February 02, 2013, 07:10:00 AM

Title: trap and center cut questions
Post by: rockkiller on February 02, 2013, 07:10:00 AM
This my my first post,although I have been following this forum for quite awhile.First off I want to thank you guys for all the help you have given me and other newbies.
I am trying to make my first glass laminated longbow and my first question the is the riser is dymondwood(1 3/4 x1 1/4 x18). How close to center should it be cut?
My other question is what are the pros and cons of trapping one side of the limb or the other.I have some custom longbows that are trapped,back wide,belly narrow and I have seen other brands trapped the opposite way. Is there a advantage to one way?And what would that advantage be?   :confused:
    Thanks
Title: Re: trap and center cut questions
Post by: JamesV on February 02, 2013, 07:26:00 PM
When I see a glass bow with trapped limbs I know the boyer missed the stack thickness and trapped the limbs to reduce the draw weight. All wood bows are a different animal when it comes to trapping the limbs but I will let the guy that build them post their opinions.
Title: Re: trap and center cut questions
Post by: kennym on February 02, 2013, 07:29:00 PM
I've trapped both ways, one to see if it gained anything(didn't) and a couple to lose 3-5 #

I can't tell any advantage for performance. Maybe somebody else has seen something I missed.
Title: Re: trap and center cut questions
Post by: Trux Turning on February 02, 2013, 07:52:00 PM
If you reinforce your riser with some extra glass on the back you can cut it to center. As for trapping- it's a good way to drop weight but you can do basically the same thing by rounding over the edges- I don't believe there is a performance gain by trapping.
Title: Re: trap and center cut questions
Post by: jsweka on February 02, 2013, 08:18:00 PM
In Jack Harrison's book, he claims that you do gain performance by trapping because it removes mass from the limbs, and that it is better to trap with back narrow/belly wide.  His explanation for this is that materials are stronger in tension than compression,therefore you need less material on the back compared to the belly.   :dunno:  That's what he states in his book anyway....

I've only trapped one bow and that was because I was about 10# over weight.  By trapping and reducing the limb width a little I was able to go from 70# down to 60#.  But I would rather get my stack right from the get go than having to adjust afterwards.
Title: Re: trap and center cut questions
Post by: rockkiller on February 02, 2013, 08:36:00 PM
So how far off center should I go????
Title: Re: trap and center cut questions
Post by: jsweka on February 02, 2013, 08:55:00 PM
I generally make mine 1/8" - 1/4" out from center.  It ends up being a little more once a side plate of leather is added.
Title: Re: trap and center cut questions
Post by: tenbrook on February 02, 2013, 09:14:00 PM
Cut to center.

You'll be FINE with that dymondwood.  VERY strong stuff!
Title: Re: trap and center cut questions
Post by: Hill Hunter on February 02, 2013, 10:02:00 PM
I am building one now and trapped limbs as part of the design (trying Harrison's suggestion)
I really like the way it looks, still a couple of warm days from shooting it much, and those are few and far between now.
Title: Re: trap and center cut questions
Post by: BigJim on February 03, 2013, 12:17:00 AM
I trap every bow I build before I even weigh it. It is a personal thing, but I have always felt they draw smoother that way and I have never liked the look of an un trapped limb.
Bows just look unfinished if they aren't trapped, at least to me.

BigJim
Title: Re: trap and center cut questions
Post by: LC on February 03, 2013, 12:44:00 AM
Big Jim I love the looks of your bows and drool over the pics I see in different threads. BUT I've never had the pleasure of fondling or shooting one of your bows. So do you trap belly being wider or back being wider? And now that your are making a recurve are you still trapping?
Title: Re: trap and center cut questions
Post by: rockkiller on February 03, 2013, 08:43:00 AM
Thanks for the info,right now I'm as dumb as a post,but with yer guys help I might just catch up with that post.   :bigsmyl: