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Hazel longbow, 100# @ 28"

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FilipT:
My goal is 90# (or maybe even 100#), if it's so unnecessary heavy now, than I still have some shaving off to do, which will hopefully remove excess weight. I even plan to heat treat it as I bought heat gun.

FilipT:
Took the string we are talking about these few last pages and got it to dangle a bit and than pulled to about 100# like Badger and Del said. Like I said, it is about 100# at 20".

Than I took the pre made FF string which is not exactly suitable for shooting this bow because of its thin loops and braced the bow with it. I did this as LAST RESORT, because that spectra fishing braid wouldn't ever stop stretching. I risked everything just to finish this bow and I dare to say it paid off.
I braced it with ease and looked at the profile. String stretched just a tiny bit and I measured that brace height dropped about 5 mm since initial bracing and then stopped. Nothing severe like the spectra obvious brace height dropping.

When I put the bow on tiller I immediately noticed on left limb (lower limb) hinge that will develop soon if I am not careful. Coincidentally and interestingly, hinge on the lower limb is almost exactly same distance as the kink on the right limb (upper limb). Marked this place to avoid it in future.
Profile was a bit uneven, upper limb was weaker and lower was stronger. I rasped the lower limb to correct this. After not too much rasping and scraping later, I put the bow again on tiller, this time connecting the scale to pulley.

It read 100# at 18". I removed the string and scraped lower limb a bit more and upper a bit less. Now again on the tiller I got 100# at 20". Limbs look very even. I called quits for today as it's so dark outside and in my garage (despite the light bulbs) that eyes are playing tricks on me. I will continue tomorrow.

Question:
Is there a math that will estimate draw weight in current state at 28" / 29"?

WillS:
If it's braced properly (between 4 and 6") and reading 100lb at 18" you're looking at 166lb if nothing else changes (which it will) at 30", or 155lb at 28".

You're going to lose a lot of weight as you get your eye in, muck about with the tiller, second guess yourself etc.  The reflex will pull out as well.  I'd say you'll be left with pretty much exactly 140lb at 30" if everything goes very well.

Del the cat:
Sounds like you are on track, but don't rush.  :)
The moral of the story, is use decent string material....
Del

FilipT:
Yes, it's 6" brace. Reflex is almost gone too. What do you think how much wood will this bow loose till it gets to 100 at 28". Just so I know the estimate, are we talking about millimeters here or scrapings?

Yes, Del, it's radically different feel when you have non stretchy stringer and non stretchy string. What a feeling to finally see this bow braced! I must now go slowly, tomorrow I will try photographing the bow so I can put it on computer to see better bend and where to scrape.

I learned so much from my errors on this bow. Definitively I am going much wiser to the next longbow projects. But the biggest thing is still estimating at beginning how thick to leave staves so I don't have over excessive wood removal to get to target weight. It's obvious that I underestimated initial thickness of this bow and that is why I have such strong wood. Also there was this "hazel is soft wood" theory at the back of my head during shaping. "Oh, it's hazel, make it much thicker!" Yeah sure, do that and feel pain hahaha.

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