Author Topic: To Facet or not to Facet???  (Read 2173 times)

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Offline Easternarcher

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To Facet or not to Facet???
« on: April 06, 2012, 12:52:45 am »
I've done it both ways an dfaceting gives a nice low crown to thew belly usually depending on design..., but Iwonder if faceting the belly when tillering works better for some bellywoods than others? ie IPE vs Osage, or yellowheart?

I'm talking mostly laminated backed bows here.
Thanks

Offline Pat B

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Re: To Facet or not to Facet???
« Reply #1 on: April 06, 2012, 01:08:42 am »
Both osage and ipe are strong enough to handle most any backing and core without trapping. I've never used yellowheart. On my first boo backed lam bow I had to trap the boo backing because it was overpowering the osage belly and the bow was taking on set. I can't remember what the core was. The trapping reduced the stresses enough so the bow didn't "set" anymore after that. I believe the problem was more operator error (  ::) ) than the boo overpowering the belly...but trapping the back did relieve the stresses none the less.  ;)
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

mikekeswick

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Re: To Facet or not to Facet???
« Reply #2 on: April 06, 2012, 05:36:05 am »
The faceted approach is one of those things that when you perserveeer with it allows real accuracy - I'm a fan and always use this approach especially with elb's and I don't round everything off until the end of final tillering.
You should read Dean Torges book 'Hunting the osgae bow' he explains the principles far better than I can.

Offline Easternarcher

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Re: To Facet or not to Facet???
« Reply #3 on: April 06, 2012, 10:30:48 am »
So basically it IS trapping the bellywood. And I suppose that once the belly takes on a more finished crown on the belly, it can handle more stress without crysals etc.
I have Dean's DVD but it doesn't explain the theory behind it.
For some reason, I got to thinking that crowning the belly worked for some woods while a flat belly was good for denser woods like IPE.
I'll have to review my Bowyer's Bibles I think. That should help... :)

Thanks guys.

Offline Pat B

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Re: To Facet or not to Facet???
« Reply #4 on: April 06, 2012, 10:42:04 am »
EA, you are correct about using crowned or flat belly depending on the bow wood. Woods that are stronger in compression can usually handle a crowned belly where the compression forces are concentrated down the center of the belly. For weaker in compression woods a flat belly distributes the stresses more evenly so all of the entire belly shares those stresses.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline Easternarcher

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Re: To Facet or not to Facet???
« Reply #5 on: April 06, 2012, 10:57:51 am »
Pat, that's the kind of explaination I was thinking of...Thank You...
So since I am currently using yellowheart belly, I think it will require a flatter belly.
I've used it in a couple of lightweight ELB's, but this is a R/D style glueup.
(ran out of Osage) :-\

Thanks again.

Offline PatM

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Re: To Facet or not to Facet???
« Reply #6 on: April 06, 2012, 11:06:29 am »
There seems to be some confusion between the term facet and the ultimate shape of the belly. A facet is just a way of controlling the amount and location of wood being removed.
 You could facet a belly as you tiller and still completely flatten it at the end by removing the central portion.
 A smart woodworker will always break down a surface area into manageable portions rather than trying to flatten a two inch wide area at once.

Offline bigcountry

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Re: To Facet or not to Facet???
« Reply #7 on: April 06, 2012, 02:09:07 pm »
I love the faceted approach with osage type woods.  It seems to make tillering a breeze, and seem to develop less hinges than flat belly. 

Now, with ipe/boo, I like flat.  or any wood like hickory that is interlocking.
Westminster, MD

Offline Badger

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Re: To Facet or not to Facet???
« Reply #8 on: April 06, 2012, 04:25:17 pm »
  I use a slightly faceted method while I am approiaching tiller. I do it only because the wood is easier to work and remove if it is slightly faceted as I approach final tiller I start flatening it out but it will still have a very slight crown when finished. I primarily use a spokeshave on white woods but it still apllies when I use a rasp on the harder woods. I think the flatter a belly is the less prone to chysaling. I like the looks and feel of a very slightly rounded belly but mechanicaly I think dead flat is better on most woods. If you are using a rounded boo back and a rounded belly on say a 50# bow the center of that bow is more like a 100# bow and the outer edges are more like a 20# bow.

Offline Easternarcher

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Re: To Facet or not to Facet???
« Reply #9 on: April 06, 2012, 05:23:23 pm »
Well yeah, I guess I do facet some of my bows and they do thenn wind up nearly flat once tillered with only a slight crown. I get it that facetting allows abit more control of the surfaces to be reduced. So, since it's gonna rain here tomorrow, I think I'll be in the shop some.

Thanks