A Crowning Confusion

[zenmonkeyman]

I keep reading that a rounded belly compensates somehow for a high crown.  I also read frequently that a flat belly distributes compressive forces more evenly, reducing set.  There is also often mention of "trapping the belly"... What does that mean?  I have read varying opinions on ELB cross-sections being the best/worst for chrysalling.  I'm so confused and despairing of finding a definitive answer through reading all the posts.  Should the belly be rounded to match the crown?  Does the answer vary from wood to wood?  I have read variously that serviceberry is equally strong in compression and tension, and that a simple D bow is best, I have also read that the belly on serviceberry needs to be flat.  Who's right?

Is there any consensus on this stuff?

[Hillbilly]

It often depends on the wood. Most whitewoods seem to do best with a flat belly. Yew works well with a rounded belly, as does mulberry and a couple other woods. Some woods just plain don't like a rounded belly, such as black locust. Most woods can be used with a slightly radiused belly. If in doubt, go with flat or lightly radiused, especially on woods that are stronger in tension than compression. It also depends on the style of bow. English longbows usually have a round stacked belly. Most Native American -style bows have a fairly rectangular cross-section with a flat belly. Trapping is simply a trapezoidal cross-section in which the belly is a bit wider than the back. Works good with tension-strong woods that tend to chrysal, such as black locust, or with bamboo-backed bows.

[Badger]

   I have always been a bit confused here as well. According to most experts the back is usually stronger than the belly and trapping would be to make the belly wider than the back. This would be similar to a crown, I tend to make my bellies just slightly rounded for no other reason than it is easier and I like them that way. Looking forward to comments here. Steve

[George Tsoukalas]

"I keep reading that a rounded belly compensates somehow for a high crown." (Just leave the stave a couple inches longer but keep the belly flat.) I also read frequently that a flat belly distributes compressive forces more evenly, reducing set. (That's correct.  But I round bellies slightly to facilitate the use of hand tools. I round the corners too. Flat bellies are caused by the use of power tools.) There is also often mention of "trapping the belly"... What does that mean? (Most woods are stronger in tension so the thinking is leave the belly wider to compensate for a weaker compression which is true of  most woods. Trapping is leaving the belly wider than the back just like a trapezoid.)I have read varying opinions on ELB cross-sections being the best/worst for chrysalling.  (They are that's why long bows are long and flatbows can be shorter.) I'm so confused and despairing of finding a definitive answer through reading all the posts.  Should the belly be rounded to match the crown?  (No as explained above.) Does the answer vary from wood to wood?  (No, just that some woods are more forgiving of rounded bellies like osage.) I have read variously that serviceberry is equally strong in compression and tension, and that a simple D bow is best, I have also read that the belly on serviceberry needs to be flat.  Who's right? (Me )

[George Tsoukalas]

Now after having answered your questions my advice is don't worry about it and just make bows. Jawge

[Justin Snyder]

  Who's right? (Me )

Now that is funny George. I'm certainly not going to argue with it though. 

When it comes to cross-section it is real confusing to me, I just do what I feel goes with the bow style. Complicating things a little is that when someone writes a simple D-bow is best, you don't know if they mean profile or cross-section.

[George Tsoukalas]

That's another thing with the elb. They are D bow (tiller). More limb working means less strain on the belly. That coupled with their length means they can take the D cross section better. Jawge

[zenmonkeyman]

Wow, I'm impressed with the high calibre of responders!  (I think you guys scared off any dissenting opinions.     )

Hillbilly, thanks for clearing up my question about trapping, as well as the general comments on bow styles.  Very helpful!

Badger, it's reassuring to hear from one of the acknowledged experts that they have questions too... Makes me feel less dumb for asking potentially dumb questions.

George, thanks for taking the time to answer my questions point-by-point!  I have no expectation of such generosity.  I have a feeling I'll be referring back often to second-guess myself.

Justin, YES!!  I'm glad somebody else, especially a higher-up such as yourself, confirms confusion over the D-Bow designation.  I thought there was a conspiracy afoot!

A further question regarding slightly-rounded bellies:  Is it a safer profile than perfectly flat as regards chryssalling?  With back undulations and wandering crowns, would a thin spot on an edge be more likely to kink and fret with a flat belly as opposed to a slightly rounded one?  My gut says the rounded belly might offer some protection here.

Garett

[George Tsoukalas]

"A further question regarding slightly-rounded bellies:  Is it a safer profile than perfectly flat as regards chryssalling."
Chrysalling, for me, has always been a type of wood issue. Ash invariably does for me so I stopped using it. I have the washboard problem too but again they have never caused any chrysalling for me. Osage is one of those woods that just doesn't look right with a flat belly so I slightly round it and the corners. I'm just not a rounded belly fan. A little is ok. Heck I can look down and see all the rounded belly I want. Jawge

[Badger]

  Jawge, I can relate to the rounded belly when i look down.
  I just slightly round the bellies on my bows simply because it is easier to use the tools when the limb is faceted somewhat, they appear generaly flat when glanced at but do have slight round if you feel them. Steve

[Hillbilly]

Wow, I'm impressed with the high calibre of responders!  (I think you guys scared off any dissenting opinions.     )

Garett, if this place was a gun store, I'd be one of the .22s. You better listen to Steve and Jawge, they're the .700 Nitro Expresses, and Justin is at least a .460 Weatherby.   Jawge, what kind of ash do you use? I've probably built a dozen good shooters from white ash and never had a single chrysal so far. Set, yes. Chrysals, no. I've chrysaled the bejeezus out of a few locust bows, though.

[Badger]

  Hillbilly, that what I can't figure out, jawge makes the black locust bows all the time. I don't think I have finished a BL bow yet without at least some chrysaling. Ash to me can be a great wood or it can be junk, one of the most inconsistent woods I can think of. If you have good ash it is really hard to beat. I haven't yet figured out how to tell the difference without just making a bow from it. Steve

[Justin Snyder]

Wow, I'm impressed with the high calibre of responders!  (I think you guys scared off any dissenting opinions.     )

Garett, if this place was a gun store, I'd be one of the .22s. You better listen to Steve and Jawge, they're the .700 Nitro Expresses, and Justin is at least a .460 Weatherby.   Jawge, what kind of ash do you use? I've probably built a dozen good shooters from white ash and never had a single chrysal so far. Set, yes. Chrysals, no. I've chrysaled the bejeezus out of a few locust bows, though.

Whatever Steve, Im a .17 mach2, but one day I hope to be a .17 HMR.

Garrett, it shouldn't be confusing. If someone says Dbow I assume they meen tiller, otherwise they should say D cross section. The only thing I have had chrysals on was osage with thick early growth.

[Del the cat]

Now after having answered your questions my advice is don't worry about it and just make bows. Jawge

Wise words indeed, that's the way to learn what works.
Any wood will crysal if you ask too much of it.
Regarding the ELB...the clue is in the 'L'
Del

[George Tsoukalas]

It's probably  a psychological thing. I used to use  white ash. I have a friend who makes great ash bow and lives in central NH. Of all the BL bows I've made only the early ones chrysalled. Back then I didn't even know what a chrysal was. LOL.  I think I've made 6 ash bows and 4 chrysalled. A board bow and a light ash bow are the only ones that didn't. I gave the light one away and the board bow is too long and kicks like a mule. The funny thing is that ash is a good winter wood because it stiffens even less than osage. Jawge