Primitive Archer
Main Discussion Area => Bows => Topic started by: grinner on July 04, 2012, 09:26:29 pm
-
Hi i have started a hack berry bow 70" 2 inches to 1.5 midlimb then to 1/2" tips. Where should i start with limb thickness for around a 50# bow also should it be the same thickness the whole limb after fades or tapered? Thanks for the help
-
I don't know what the final thickness sould be, but on the subject of a consistant width it depends on design just keep in mind if it gets thicker it will probably get narrower and viceverca.
-
Start with 5/8" thick limbs and go from there. That should give you plenty of room to tiller. Sounds like a semi pyramid design so you probably wont need much thickness taper.
-
If it is a pyramid front profile, the thickness stays about the same.... I don't know if I have enough experience to give you a specific number or not. Maybe 5/8ths or 3/4" might be a good place to start.... each piece is different, even within a certain species... I floor tiller and then work it down with the ferrier's rasp till I get a limb bending like I want it to.... then try to get the other one to match it. I think keeping the limbs bending evenly is the big thing. I don't usually measure the thickness, come to think of it. I did on my first few bows, I think, but at some point I just started eyeballing the way the limbs were bending. I would err on the side of caution and take off a little bit at first - you sure can't put it back... ;) Good luck with it.
-
Ha! me and Okie both said 5/8ths! that is probably a good spot to start. :D
-
What kind of draw length are you going for?
-
going for a 27" draw thanks for the help
-
With only a 27" draw, a 70" bow has lots of extra lumber hanging out on the limbs. I am assuming you are doing a stiff handle and stiff fade-outs into the bow limbs. In that case, you can use the old stand-by of "(2x drawlength) + 10%".
(2x27) + 5.4 = 59.4 Or just call it 60 inches, nock to nock.
With the wide limbs (side to side) you will end up with fairly thin (front to back) cross section. Pyramid bows are a pretty safe design structurally, so shortening your limbs up should not be putting your stave in jeopardy of turning into kindling on full draw.
Post some pics, I love hackberry!
-
THanks for the help. I got it shorted to 60 inches and floor tillered. I am thinking about heat treating it but i am not sure what the moisture concrete is will it hurt if it is not dry enough? Also what is a good way to tell MC without a meter. THanks for the help
-
If you let the wood sit now at the floor tillered stage for a few weeks it should be just fine, even if it was cut green in the last few months!
Where are the pictures, where??? :(
-
I too am working on a Hackberry Bow currently. 70" ttt. 4" stiff handle, 2" fades. Width is 2" at the fades and tapers slightly to 1 3/4" mid limb. Sharp taper from there to 3/8" nocks. I marked it to 5/8" for thickness as a place to start. I don't measure it beyond that first rough measure so I can only tell you that 5/8" is probably a good place to start. Still way to thick, at least on this one.
-
Thanks for the help I will try to post picture later today. Thanks
-
Here is a back and side view of the bow. Will post more pics of the tiller as it comes along (http://i1124.photobucket.com/albums/l578/shawnbu1/DSCF2386.jpg)(http://i1124.photobucket.com/albums/l578/shawnbu1/DSCF2387.jpg)