Trapping

[Don W]

Does anyone have a list of species that work better when trapped or as a small diameter tree or sapling?

[SLIMBOB]

I have trapped a number of Osage bows with decent results. I believe Marc nailed it. It reproduces a small diameter crowned effect. I will often not temper these, as I question if having done both (crowning and tempering)might take one a bit too far. Just my sense about it, nothing more.

[willie]

tension vs compression observation, a bit of an aside

I recently found a number of well weathered but dry birch sticks. when bent to failure, all broke in tension before taking any set.

Of course, as bowyers we often cite the general necessity for using un-weathered wood, but the thought came to mind as I broke stick after stick.....

if designing for proportionally high tensile stress, extra attention should be given to wood soundness on the back

[loefflerchuck]

Jim Davis, yes. The first compression means tension. Need to proofread.

[loefflerchuck]

I’ve never trapped a bow but have noticed naturally trapped bows(small diameter) have a advantage in speed with elm and even hickory. Perhaps the whole idea of de-crowning these woods that are stronger in “tension”(got it right this time) is a bad one.

[SLIMBOB]

No question in my mind that you are right. Smaller diameter crowned bows are noticeably better performers. Decrowning might make the back less likely to break, but the net benefit in my mind is a loss in cast. I am speaking only about Osage. Can’t recall trapping anything else. Persimmon on the other hand can’t withstand the strain. High crowns have snapped every time on me.

[willie]

Perhaps the whole idea of de-crowning these woods that are stronger in “tension”(got it right this time) is a bad one.

De crowning until the back is as wide as the belly?

 you could decrown a narrow width on the back and essentially have a trapped bow. a slight decrowning as such would still spread the max stress evenly across whatever width chosen instead of concentrating it along the peak of an uncrowned back.

[Jim Davis]

My sample size is way to small to draw any conclusions, but a bow I made from a 1-1/4" serviceberry stave held on the crowned back, but chrysalled on the belly.

[bassman211]

With white woods for me belly heat treating, and trapping the back has really prevented set ,and fret. Before learning how to do both properly I was making far to many bows with set, and fret, and the bows were lazy. 100+40=133 to 136 fps. Just finished a Black Walnut bow at 36 lbs. for target  shooting  that shoots a 350 gr target arrow  at 154 fps average at my very short 25 inch draw. Nothing like DC's bows , but sure puts a a smile on my face. This one is fire hardened, and has an 8 strand D 97 string with very slightly reflexed tips. No set, and  tunes good ,and when you unstring it it bounces right back to it's original profile. With Black Walnut that is quite an accomplishment for me.

[StickMark]

Great speed, Bassman...hoping to get there, as I don't even draw an honest 27 with a Redwing recurve. SHorter draws like more efficiency.

Build mostly hickory, always trapping. Even applying sinew, keep most of the "umph" on the thin layer(s) down middle.

Once at first low brace, running the knife edge down the sides, and then sanding.

[bassman211]

Stay with it StickMark you will.

[mmattockx]

Just finished a Black Walnut bow at 36 lbs. for target  shooting  that shoots a 350 gr target arrow  at 154 fps average at my very short 25 inch draw.

That's very decent for a 25" draw. A longer draw length is a big advantage when looking for speed. The testing I have seen people do on FG bows shows every inch of draw adds significant speed when keeping arrow weight at a constant GPP.


Mark

[bassman211]

Yes , my son with 28 plus inches of draw with glass bows shoots up to 25 fps faster with the same glass bow ,and arrow depending on the bow.

[Selfbowman]

I trap most all my bows these days. Some take less set . I think it’s more about density as far as the need for the trap as in white woods. I still trap my Osage. But I think it’s back to density on all woods.
Arvin