I would like to make a comparison of flat belly tillering to faceting tillering or rounded bellies. I will start off with a disclaimer, these are just opinions on my part and could easily be wrong. I change my opinions about things all the time. Years ago I noticed that my thicker cross section bows seemed to maintain their profiles better than my flat bows, the flat bows were taking more set. At one level it didn't really make sense but on another level it did and I refused to look at it. I make 90% of my bows with at least slighty rounded cross section and I will likley continue to do so, I also use a faceting tiller method to bringing my bows to the string, I will also continue to do that. I feel it is safer, more foregiving and physicaly a lot easier and faster. It also makes fine bows!
My arguement against it is that if we are trying to push for as much as we can get out of a bow a flat design will have it beat for a number of reasons. It simply strains the wood more evenly and damages less wood cells. Damages wood cells are a major source of loss in wood bows that modern bows don't have to deal with. A rounded belly will hide most of these losses because the tension wood will simply pull most of it back into place when we unbrace it. The evidence can be felt in the tightness of the string on a braced bow. The rounded belly might take 1" of set while the flat bow may have taken 2" of set but the string will still be tighter on the flat bow most of the time. The same thing would apply to bows made too narrow. Just looking at my own fastest bows the majority have had mostly flat bellies. From the few very flat ones I have done recently it also looks like they may carry less mass weight. This could only be true if it were due to wood cells being crushed and carrying around some dead weight. Any opinions??
