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Main Boards => The Bowyer's Bench => Topic started by: TheUnatural on May 02, 2013, 10:20:00 PM

Title: Flat vs. Round Belly
Post by: TheUnatural on May 02, 2013, 10:20:00 PM
I am currently planning out a bow right now (sinew-backed Juniper) that is going to have a set-back handle area, as well as some slight recurve on the tips. I have been reading as much as I can about similar bows, but I have come to a bit of a problem.  I have seen some information regarding the belly x-section that has been contradictory, i.e. flat vs. round. The only bow I have seen that was similar in materials and shape (SB'ed Juniper with recurve) had a round belly (to help prevent splintering, chrysalling, etc). But I was just reading vol. 3 of TTB, and Jim Hamm stated that bows with this kind of curvature require a flat belly (to handle the compression). Does anyone here have any idea about the route I should take? Unfortunately, I really can't experiment with the two designs (lack of resources and time). Any help would be appreciated.
Title: Re: Flat vs. Round Belly
Post by: John Scifres on May 02, 2013, 10:42:00 PM
A well-built round belly bow may compress more and follow the string a bit more but will have less mass at the tips so it will still be an efficient bow.

A flat belly bow may follow the string less and can be very efficient but it loses something in the aesthetic.

In the end, you can make a beautiful, great shooting bow either way.  But don't expect your first one of any style to be great.  You will have to put resources into it to have a good result.  In other words, your first or fifth or tenth may not meet your expectations no matter what style you choose.
Title: Re: Flat vs. Round Belly
Post by: mwosborn on May 03, 2013, 12:05:00 AM
I recently finished a sinew backed erc.  I went with a rounded belly.  I had read that the compression of erc was good and could handle the rounded belly. It turned out to be a really nice shooting bow.  I can send you pics if you want.
Title: Re: Flat vs. Round Belly
Post by: TheUnatural on May 03, 2013, 12:11:00 AM
QuoteOriginally posted by mwosborn:
I recently finished a sinew backed erc.  I went with a rounded belly.  I had read that the compression of erc was good and could handle the rounded belly. It turned out to be a really nice shooting bow.  I can send you pics if you want.
Please do. Did you put any curves in your bow? And how much heartwood did you manage to get in the belly?
Title: Re: Flat vs. Round Belly
Post by: Bowjunkie on May 03, 2013, 06:05:00 AM
I make all of my bows with a rounded belly. Flat flatbows just ain't done yet  :)
Title: Re: Flat vs. Round Belly
Post by: Bob at Work on May 03, 2013, 08:27:00 PM
can you post pics of the erc?
Title: Re: Flat vs. Round Belly
Post by: mwosborn on May 03, 2013, 11:55:00 PM
Here are a couple pics - thought I posted some here a while back, but can't find the post!

UN - I did not put any curves in it.  The sinew has kept it dead straight with no set.  Been shooting it for a couple of months now.  I really like the way it shoots and will definitely make some more from erc!  I am sure you could curve the tips some - although I have never tried to bend erc.  I did not use heat on this one at all as the stave it came from was nice and straight.

 (http://farm9.staticflickr.com/8510/8544750027_2eea90a7e1.jpg) (http://www.flickr.com/photos/92150841@N03/8544750027/)
IMG_1963 (http://www.flickr.com/photos/92150841@N03/8544750027/)  by  mwosborn1 (http://www.flickr.com/people/92150841@N03/) , on Flickr

 (http://farm9.staticflickr.com/8531/8545845576_9b54a602d3.jpg) (http://www.flickr.com/photos/92150841@N03/8545845576/)
IMG_1964 (http://www.flickr.com/photos/92150841@N03/8545845576/)  by  mwosborn1 (http://www.flickr.com/people/92150841@N03/) , on Flickr

 (http://farm9.staticflickr.com/8382/8545844744_f9b5f1cf6b.jpg) (http://www.flickr.com/photos/92150841@N03/8545844744/)
IMG_1962 (http://www.flickr.com/photos/92150841@N03/8545844744/)  by  mwosborn1 (http://www.flickr.com/people/92150841@N03/) , on Flickr

 (http://farm9.staticflickr.com/8105/8544749197_181be60147.jpg) (http://www.flickr.com/photos/92150841@N03/8544749197/)
IMG_1961 (http://www.flickr.com/photos/92150841@N03/8544749197/)  by  mwosborn1 (http://www.flickr.com/people/92150841@N03/) , on Flickr
Title: Re: Flat vs. Round Belly
Post by: Bowjunkie on May 04, 2013, 07:01:00 AM
mwosborn, that's nice. What are the specs on her? Length, width, draw weight, etc?
Title: Re: Flat vs. Round Belly
Post by: TheUnatural on May 04, 2013, 11:19:00 PM
That big knot in the last pic doesn't affect the bow at all?
Title: Re: Flat vs. Round Belly
Post by: takefive on May 05, 2013, 04:27:00 AM
Beautiful bow    :thumbsup:
Title: Re: Flat vs. Round Belly
Post by: Igor on May 05, 2013, 06:13:00 AM
the post of the ERC by thenatural.....


http://tradgang.com/noncgi/ultimatebb.php?ubb=get_topic;f=125;t=009755;p=1#000000
Title: Re: Flat vs. Round Belly
Post by: PEARL DRUMS on May 05, 2013, 06:49:00 AM
I keep low compression woods flat with slightly rounded edges and high compression woods getting rounded off. The highest point does the most work, it only makes sense to me.
Title: Re: Flat vs. Round Belly
Post by: mwosborn on May 05, 2013, 03:33:00 PM
The knot doesn't seem to bother anything.  I just followed the grain around it.  This was about as knot free erc that I could find.  

Looks like Igor found the other post - it has the specs if your interested.
Title: Re: Flat vs. Round Belly
Post by: Roy from Pa on May 05, 2013, 07:53:00 PM
Very nice bow.
Title: Re: Flat vs. Round Belly
Post by: mwosborn on May 05, 2013, 11:00:00 PM
Thanks Roy - slowly learning!   ;)
Title: Re: Flat vs. Round Belly
Post by: LittleBen on May 06, 2013, 08:45:00 AM
Very nice ERC. I like th elook of mixed sapwod and heartwood. I will have to try one like that with nearly all sapwood.

Regarding the flat belly vs round, I agree it's not that big of a deal, obviously the absolute most efficient design is a flat belly, with that said, if you prefer the look of a rounded belly, I say go for it. No one shoots trad bows for the smoking unbeliuevable speed and performance ... what is a couple FPS really.

I keep all mine for the most part flat for two reasons, one I think it's harder to get a perfectly even and smooth looking round belly, I like the mix of old and new you get with a wood bow having a flat profile like the fancy factory bows.
Title: Re: Flat vs. Round Belly
Post by: TheUnatural on May 06, 2013, 10:36:00 AM
Yeah, that's a great looking bow! Thank you for the pics, hope mine turns out half as nice. Well, I guess I can at least hope mine doesn't snap in half from the strain of the design.
Title: Re: Flat vs. Round Belly
Post by: burnt on May 06, 2013, 12:14:00 PM
Use to make round belly bows but like John I found the limbs took on more set than I liked. Lately I make flat belly bows that slowly transition into a round profile towards the tips starting somewhere in the midlimb.  That being said ERC looks really nice with a round belly.  Highlights the wood more.
Title: Re: Flat vs. Round Belly
Post by: Pat B on May 07, 2013, 01:42:00 PM
I agree with what Pearlie said. radiused belly for compression strong woods and flat belly for everything else.
Very nice looking bow, mwosborn. Sinew backed ERC is on my list.