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Main Boards => The Bowyer's Bench => Topic started by: styksnstryngs on May 05, 2017, 11:43:00 AM

Title: Safe thickness of window?
Post by: styksnstryngs on May 05, 2017, 11:43:00 AM
Hey guys, I'm drawing out plans for a TD longbow and I wanted some input about safety. The riser is a slim riser, like a pronghorn or similar riser. I'm planning on sandwiching walnut, 1/4" phenolic, glass, 1/4" phenolic, and walnut. Do you think I could cut 3/16" past center on a 1.5" wide riser?
Title: Re: Safe thickness of window?
Post by: Crooked Stic on May 05, 2017, 07:47:00 PM
Phenolic and wood expand and contract at different rates. If you must use it for accents be sure to rough the glue surfaces good .36 grit or even a hacksaw blade. You better choice would be a stronger wood with the walnut such as a osage ibeam. Also glass overlays on the front of the riser.
Title: Re: Safe thickness of window?
Post by: mikkekeswick on May 06, 2017, 02:18:00 AM
The key is just making sure you get the walnut dry enough first.
Personally I would use a glass or carbon I-beam if you want to cut so far past center. With the combo you have I would go to centre and no further.
Title: Re: Safe thickness of window?
Post by: Crooked Stic on May 06, 2017, 10:44:00 AM
Another thing would be to get you walnut stabilized.
Title: Re: Safe thickness of window?
Post by: styksnstryngs on May 06, 2017, 04:06:00 PM
Alright, the thing is, I really can't use an I beam because of a limit of tools I have. If I have to, I will, probably using three pieces of core tuff, but I would prefer not to. Would five or six pieces of .030 core tuff as accent strips work?
Title: Re: Safe thickness of window?
Post by: Roy from Pa on May 06, 2017, 04:32:00 PM
I'd go for it. What weight bow?
Title: Re: Safe thickness of window?
Post by: styksnstryngs on May 06, 2017, 04:33:00 PM
Probably 45# or less, nothing too heavy.
Title: Re: Safe thickness of window?
Post by: styksnstryngs on May 06, 2017, 04:34:00 PM
How strong would a 1/4" phenolic  I beam be?
Title: Re: Safe thickness of window?
Post by: Roy from Pa on May 06, 2017, 04:35:00 PM
It will be fine then.
Title: Re: Safe thickness of window?
Post by: jess stuart on May 06, 2017, 06:43:00 PM
Coretuff on the back of the riser will help a bunch.  Also be sure you radius the site window junction well.  While walnut is a very pretty wood it isn't the strongest, I would never personally use walnut and cut 3/16" past center.  I assume you are building your bow 1.5" wide so, the window would be 9/16" thick.
Title: Re: Safe thickness of window?
Post by: Crooked Stic on May 06, 2017, 11:01:00 PM
You can use the wood accents. They can be oriented in the width also. The phenolic will be plenty strong just ruff up the glue surface really good. And be sure the MC on the walnut is low. Be sure you get a good seal on the riser after done.
Title: Re: Safe thickness of window?
Post by: LittleBen on May 08, 2017, 10:10:00 PM
Everyone likes to ask "how heavy is the bow?" Or "how far part center?". But remember, the longer the bow, the more stress that is on the riser. So what would be safe for a 56" bow might not be for a 70" bow.

Just my .02

I've never had a bow fail at the shelf/window and Ive cut many to center or slightly past with all wood risers on all wood bows up to 65# and 68" with 1.5" width. So personally i say go for it! What fun is it to live by strict rules?

Live free or die.
Title: Re: Safe thickness of window?
Post by: BenBow on May 10, 2017, 04:58:00 PM
I add additional wood and glass to the outside of the window equal to the amount past center the window is cut. Plus I put .030 glass between 5/16" hickory and locust lams and .030 glass and 1/16" phenolic between the back and belly halves. And this is a very thin riser that's 1 1/16" wide at the pads and is cut 1/4" past center. It's very solid.
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