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Main Boards => The Bowyer's Bench => Topic started by: hickry on January 22, 2009, 02:21:00 PM

Title: How narrow can tips be?
Post by: hickry on January 22, 2009, 02:21:00 PM

Hi guys,
I'm reading through my new copy of TBB4... AWESOME!!  The "eiffel tower" design looks pretty neat and I'd like to try and build a bow on that principle.  I'm still pretty new to building these things and have a LOT of questions.  My question now is on the limb tips.  They mention narrowing, and thickening the limb tips to reduce mass... just enough to prevent them from bending and taking a set.  Does anyone know of a test that may help estimate, at a given width, what the thickness should be to keep them stiff?  I'm just trying to get a feel for where to start...

Title: Re: How narrow can tips be?
Post by: No-sage on January 22, 2009, 02:46:00 PM

Tips can be 3/8 round without any problems.

Much depends on your skill.  If you're looking for a place to start, just make a few regular flatbow, learn to tiller, then you might want to think about getting fancy.

Title: Re: How narrow can tips be?
Post by: Pat B on January 22, 2009, 03:26:00 PM

I agree with no-sage. Learn how to tiller first then you will be able to do lots of cool stuff with your bows. If you start with the tips you may have nice tips with nothing in between.
   The tips are the last thing I shape on a bow. I want to be sure the string tracks good when the bow is braced so I concentrate on that first. I leave the tips at least 1/2" or wider to start. When reducing the tips leave them thick(1/2"or so). This way when you are ready to narrow them you will have plenty of strength from the thickness to get then narrow. I usually go to 3/8" on finished tips but I have seen scary narrow tips on 60# bows.     Pat

Title: Re: How narrow can tips be?
Post by: Aeronut on January 22, 2009, 06:59:00 PM

Like Pat said, dom the tips after your tillering.
Mine are just under 1/2" at the string nock and 3/8" past it.

  (http://img.photobucket.com/albums/v511/aeronut/Curly%20Hickory%20Bow/DSC04415.jpg)

Dennis

Title: Re: How narrow can tips be?
Post by: hickry on January 22, 2009, 07:43:00 PM

Thanks!!!

Title: Re: How narrow can tips be?
Post by: Springbuck on January 22, 2009, 09:55:00 PM

I have made #50-plus bows with 1/4" wide tips.

  I like making these, esp. Holmegaard designs and I use the rule: double the width=double the stiffness.  Double the thickness=8 times the stiffness.  That's kinda the whole point; thicker tips can be stiffer and weigh less than wide tips.

  Like say you want stiff tips about 10" long. If a it's 1/2" thick and 1-1/2" wide, start about 12" down, thicken it to 5/8" over several inches, while narrowing it to 3/4".  Then leave it 5/8" thick, while you narrow the tips to whatever final width will be, like 3/8 or whatever..

Title: Re: How narrow can tips be?
Post by: Roy Steele on January 29, 2009, 12:57:00 PM

Self bows I like to keep them three eights.For bows up to 66" long you could go smaller with a longer bow.
   But remember heaver the tips the less hand shock.

Title: Re: How narrow can tips be?
Post by: Apex Predator on January 29, 2009, 01:42:00 PM

I think you have that backwards Roy.  :)

Title: Re: How narrow can tips be?
Post by: Roy Steele on January 29, 2009, 08:01:00 PM

Sorry but Ive built alot of bows.And if you leave them a litte heavy and stiff it will help hand shock.Along with not letting it ben into the handle.And also brace it low as possible.
  But I could be wrong I am use'ly.