Post by: Burnsie on December 14, 2023, 10:06:02 AM
Here are a couple pics of where I'm at. First pic is braced at about 6.5", the second pic I have the bow pulled to about 20" draw. I had it pulled to just shy of 23" last night with the scale reading 49.5 lbs. I'm hoping for a 48-50# bow? At this point, do I just scrape a bit off both sides evenly over the whole length of the limb and keep checking weight until I get out to my draw length (about 27.5"). Any critique is welcome - the shape of the bow so far, or anything that might look funky?
Thanks Again!
[ You are not allowed to view attachments ] [ You are not allowed to view attachments ]
Post by: mmattockx on December 14, 2023, 10:42:37 AM
Mark
Post by: Burnsie on December 14, 2023, 10:52:48 AM
Left limb looks decent. I wouldn't touch the outer limb and would do some scraping coming off the fades to about 1/3 out to get that moving more. The right limb looks to have a hinge about 1/3 out. I would only work on the fade area on that side and the outer part of the limb to get both moving or that hinge will sewer you.
Mark
Yeah -I see what you mean, I'll tape that area off so I don't touch it moving forward.
Thanks
Post by: Mo_coon-catcher on December 18, 2023, 07:15:41 PM
Kyle
Post by: Burnsie on December 18, 2023, 10:37:46 PM
I think I've made some progress - when I get a chance I'll take another pic with it drawn closer to 25" and
see what you guys think.
Post by: Pat B on December 18, 2023, 10:49:39 PM
Post by: Roy from Pa on December 19, 2023, 07:04:12 AM
Post by: Burnsie on December 19, 2023, 04:10:52 PM
That oval really tells the story.
I just have a terrible eye for identifying these type of things.
Post by: Roy from Pa on December 19, 2023, 04:27:22 PM
I used the paint app in windows to do that. Very easy...
Post by: Burnsie on December 19, 2023, 11:35:39 PM
Do self bows follow the rule of gaining about 2# per inch of draw? If so, at 28" we're looking at about 56#
I'd be happy with a bow even down to 45-46#, so need to loose 6+ lbs.
[ You are not allowed to view attachments ]
Post by: Roy from Pa on December 20, 2023, 11:46:55 AM
Looks better but still flat at fades, especially right limb.
Yes about 2 pounds per inch gain on draw.
You really do not want to pull a wooden bow past it's intended final weight.
I'd thin up those flat areas plus scrape both limbs to reduce the weight.
It looks like the edges of your limbs are square?
That is asking for trouble.
They should be rounded over, that will take some weight off too..
Post by: Pat B on December 20, 2023, 11:29:04 PM
Post by: Burnsie on December 21, 2023, 09:21:08 AM
Merry Christmas.
Post by: Honest Jon on December 27, 2023, 07:36:32 PM
Please consider that I know nothing about the build progress of this bow other than what is shown in this thread. Based on that info I think you’re going to have to drop the draw weight down to about 36-38# in order to have a chance at salvaging it. Think about the hinge area outside the fades on the right limb as the weakest link in a chain. Actually, the weakest part of your bow. Just eyeballing here but it looks like that spot can not stand more than about 38# of draw. So, you’ll need to leave that spot alone and balance the rest of the bow to about that draw weight. Just my thought.
Honest Jon
Post by: Roy from Pa on December 28, 2023, 07:47:22 AM
Jon has a valid point.
You need to mark an inch out on both ends of the hinge area and never touch it again.
Get the area from the hinge inward towards the handle bending some first.
Get the other limb fade bending some to.
You need to make a tillering gizmo and use it to tiller.
https://www.3riversarchery.com/blog/how-to-make-and-use-eric-krewsons-tillering-gizmo/?gad_source=5&gclid=EAIaIQobChMIiqa0kpaygwMVr0xHAR12IwE5EAAYAiAAEgLL6_D_BwE
Post by: Burnsie on December 28, 2023, 10:26:29 AM
I built this gizmo with directions from Kramer (Shatterproof Bows), but never really knew how to use it.
Thanks for the info from Eric Krewson - that spells it out pretty good.
[ You are not allowed to view attachments ]
Post by: Roy from Pa on December 28, 2023, 10:59:16 AM
Yes use the gizmo, they really work well. If you have any questions about it, send me a PM.
Post by: Roy from Pa on December 28, 2023, 11:02:21 AM
Post by: Roy from Pa on December 28, 2023, 11:03:10 AM
Post by: Roy from Pa on December 28, 2023, 11:21:37 AM
Post by: Honest Jon on January 01, 2024, 10:09:52 AM
I don’t think you are, but please don’t be discouraged. You’ve done some nice things to this bow already and with a little more sorting it can likely be a bow you’ll enjoy and be proud of. I’m still very much an amateur bowyer after building some 40 bows. At least ten of which blew up at late stages of the build. It can be deflating! On the other hand, I’ve built some beauties including my favorite hunting bow. Hanging on my wall alongside about a dozen of my bows, I keep the remnants of a bamboo-backed Osage bow that exploded just after I thought it was finished. I’m still not sure why it broke. Could be an error on my part or it could be the nature of the wood.
Hang in there!
Jon
Post by: Burnsie on January 12, 2024, 05:30:13 PM
Jon - All is well, no discouragement here - I'd never let something like a self bow ruin my day. I enjoy being in the shop, shaping wood and learning. If this one doesn't work out, I have plenty more roughed out and many staves seasoning in the shed.
Right now I have the bow to the point where I am reasonably happy with it, even though I know it wouldn't pass inspection with most of the very experienced bowyers on this forum. I may bring it down to the Tennessee Classic this Spring and see if someone will help me perfect the tiller - or tell me its a lost cause??? Here is a recent pic.
Also, what is the preferred cross-section profile of a typical Osage self bow limb? I know you want to round over the edges, but to what extent. How much rounding do you want to do on the back of the bow without violating a a bunch of growth rings? I included a rough sketch below, what version do you want your cross-section to look like? I drew the back of the bow straight across, more than likely it will have a bit of a convex shape to it due to the natural shape of the stave and circular rings.
Post by: Mad Max on January 12, 2024, 06:38:54 PM
Come to the classic and join the bow challenge, plenty of help and I'm sure you will build a great bow.
Build the bow and shoot the target range for a trophy , lots of fun for the whole family.
up to 800/900 people there on Saturday
Post by: Roy from Pa on January 13, 2024, 06:00:56 AM
On the next one try getting the bend starting closer to the end of the fades.
[ You are not allowed to view attachments ]
[ You are not allowed to view attachments ]
Post by: Roy from Pa on January 14, 2024, 09:26:11 AM
Post by: Kirkll on January 14, 2024, 11:16:18 AM
Looking better.
On the next one try getting the bend starting closer to the end of the fades.
Why would you want that bow bending closer to the fades? That doesn’t make any sense to me…
Post by: Roy from Pa on January 14, 2024, 01:17:30 PM
Post by: mmattockx on January 14, 2024, 08:58:25 PM
Match the belly to the crown on the back, radius as a green pea all 4 corners. :thumbsup:
This I will disagree with. The most efficient cross section is a rectangle but you can't have that when following a ring on the back. You can have a flat belly, though and that minimizes the compression stress on the belly wood by spreading it as evenly as possible and reduces the chance of taking set or getting chrysals.
Definitely want to radius the corners, especially on the back. I only radius mine maybe 0.08"-0.1", though, never as much as the recommended pea size. A bigger radius doesn't hurt, it just takes a bit of performance away for more margin on lifting a splinter. YMMV.
Why would you want that bow bending closer to the fades? That doesn’t make any sense to me…
Wood can't take the strain that FG can, so you get better performance by getting the whole limb to bend and share the strain more equally. If you concentrate the bend all in one spot like you can with FG you overstress the wood and end up with a bunch of set and poor performance.
Mark
Post by: Kirkll on January 14, 2024, 11:57:53 PM
Post by: Mad Max on January 15, 2024, 08:18:42 AM
It's Osage
Have you ever tried to scrape a belly flat, your scraper needs to be real sharp and it's not easy.
A rounded/faceted belly is easy to scrape and makes a great looking bow also.
Remember we are teaching Newbie's here. All the bows I see at the Classic for teaching newbie's to be successful making and shooting bows are radius belly.
Yes a flat belly would/could have more performance, not sure
A pea give some reference to size
Here is 1 reference to the subject
https://www.tradgang.com/tgsmf/index.php?topic=160919.0
Post by: Roy from Pa on January 15, 2024, 09:09:47 AM
Every bow I've made in 15 years has had a rounded belly.
Post by: Mad Max on January 15, 2024, 09:20:11 AM
All I make are wood/bamboo backed bows.
Every bow I've made in 15 years has had a rounded belly.
Me thinks it's been more than 15 :laughing:
Post by: mmattockx on January 15, 2024, 11:11:57 AM
It's Osage
Have you ever tried to scrape a belly flat, your scraper needs to be real sharp and it's not easy.
A rounded/faceted belly is easy to scrape and makes a great looking bow also.
Fair enough. Osage is also much more compression tolerant than the woods I have to work with up here, so those small details matter more for me.
Every bow I've made in 15 years has had a rounded belly.
I didn't say it won't work, I said a rectangle is the most efficient shape.
Mark
Post by: Honest Jon on January 15, 2024, 06:41:17 PM
Jon
Post by: Kirkll on January 19, 2024, 03:12:26 PM
The guy who makes all my bows has a rounded belly too…and he looks a lot like me😆 :knothead:
Jon
Now THAT.... was funny! :biglaugh: :biglaugh: :biglaugh: