Primitive Archer
Main Discussion Area => Bows => Topic started by: Strong Leaf on September 01, 2012, 06:07:30 pm
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The bow is near completion and is measurements are 60" NTN that is pulling 38#@13inches Osage orange
It has a slight gradual cure side to side like a "(" shape. When it is braced the string (58" Fast Flight 16strand) lays on the right side to center line ,,which I feel is fine because I am shooting left handed. There was A big knot that I placed in the handle area located a bit left of centerline on the bottom part of handle as shown in last pic. I feel the wood is thicker on the curved side but tapers across the belly to the straight side. I am just using a four-in-one rasper to rasp down along both limbs going from center to tips of limbs. And leaving the tips a bit thicker then the inner 2/3 of limb. As I remove wood I am following the natural shape of the body. I am just seeking advice on how to get the bow to pull 55-60# @ 28". Thank you for reading and I have to just say that this this site PA is has the greatest group of people who support , who are unbelievably talented, and posses hard to acquire skills.
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You are definitely going to have to narrow it down some.......at least the tips. Looks way to wide judging from your hand.
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Few things. I would get the front view profile finished at this point. You can leave the tips wide as you work one down, but at a point you have to narrow to it's finished shape. For me, once I have a string on it, the shaping has been finished (there are exceptions to this but no need to go there). You are tillering now, so most of the wood removal will come from the belly. As stated above, I would get the tips narrower for sure, 1/2" wide or so. Make sure your thickness taper is even on both sides of the limb (use a caliper or a crescent wrench). I mention this because you said, I think, that the limb is thicker on one side.
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Thanks beetlebailey and slimbob for the responses ,, On the top limb 20" out From the middle of the bow is 1.6875 inches wide and tapers to 6/8(the tip) . And 20" out from the middle of the bow towards the bottom limb starts @ 1.75 inches wide and tapers to 0.6875 (5/8+1/16) for the outer 3rd of the limb . ,,, I am going to bring both tips to 1/2 ,,,, would an inch @ the outer 3rd be a good width that tapers for the last 10 inches to 1/2 inch @tip ??? Thanks again
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How wide are you planning on having it be at the widest point (the fades)? It seems unnecessarily wide at this point judging from the pics. Osage is a dense wood with good compression. It can tolerate being narrower than many woods and that allows it to reduce it's mass thus improving cast. With that flat bow style you have going I'd say 1 1/2" should be plenty wide for the weight you want. Maybe someone with more osage experience will correct me but that's my humble assessment. Any wider than that and I think it will just make the bow a bit sluggish.
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I agree on narrowing it at this stage. After taking the sides down you might be around the weight you wanted with mabe a little more taken off the belly to finish.
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When I first started making these Bois d'ark self bows, mid 90s, mine were 2" wide and all under 60" long. I now make most longer, around 64-66", and 1 1/2" wide, some around 1 1/4". If the wood is more dense than average (wider growth rings with a small percentage of early growth, say 10-15%) go narrow. If it appears less dense than average (narrow growth rings and lots of early growth) go wider. Still 1 1/2" width at the fades seems to be a good mark for me. Narrow tips regardless.
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Thanks for inputs :) I am narrowing today. And at the fades it gets pretty wide ( 2+ inches ) because the knot that I mentioned above starts on the right edge just below handle on the lower limb and goes diagonally through the bow and stops around center line on the belly. It has a rotted center and I am hoping to just fill it in on the belly with some real " running " superglue. I would of made it alot thinner but I am just playing it safe with the diagonal knots (one more on top limb the starts on edge and also goes inward&downward towards centerline) thanks again everyone :)
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here are pics of 1/2 " tips ,,I am still narrowing whole profile
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Post a pic of the knots your talking about, and the handle area. Keep in mind, it's one thing to say "make it 1 1/2" wide", but if there are knots or other peculiarities, you may need to go wider at those spots. I'm curious about the knots you mentioned.
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here they are...both fall on the right side of the back of the bow,and on the bottom limb.
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You wanted tiller advice, so here goes, IMO the left limb is wirking a tad hard win the outer 1/3 - 1/2 where the right limb is a tad stiff in comparison.
I'm assuming the right limb is the lower one hence the slighter stiffness.
The extra tip width is fine during early tillering as it give you room to adust the string line, but like the other guys say, now you can be slimming it down.
Personally I tend to leave a hint of extra width until it's had a few arrows through it, in case it needs some fine adustment of string line.
(I'm a tad worried that there doesn't seem to be extra thickness at the grip to compensate for where it gets narrower).
Del
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I'm a tad worried that you don't seem to have chased a back ring on this bow.
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If you've de-crowned it on purpose ok but if not then back it with rawhide before going any further.
You have a few weak spots on the drawn picture - do not pull it ANY further until these are fixed.
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Well, Mark and Mike are right. Appears from the last pics you didn't follow one growth ring on the back. Do you know where to get rawhide, hide glue and have you read anything on applying a backing? If not, plenty of info on this forum, plenty of guys that will help. I would not do any further tiller work until you got 'er backed. It requires some skill and knowledge, so educate yourself before you attempt it. Must reads in TBBI, II, III, and IV. Search function on this forum. Find a bow maker close by and and get some hands on help, post pics and ask questions.
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Responses are great :) thanks again ,, I did not know about "decrowning" and thought as long as I had a single ring down the center I was alright ,,,with that said would it be possible to go as to narrow front profile view to the width of the single strip of hartwood down the middle ?? I do have the book "Bows and arrows of the native Americans " by Jimm Hamm . It does explain baking a bow with sinew . I have stopped everything and now am gathering the materials I need to back the bow . Thanks you greatly you guys :)
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Decrowning in the manner you have said is Ok on some woods, but I can't speak for Osage.
It may be ok, if there are no vioaltions across the limb.
But if the guys have suggested backing, then that's the way to go to be safe on your first bow.
Del
(I felt I just had to offer a word of agreement with your thinking)
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There are guys on here far more experienced than I when it comes to sinew backing, so solicit more advice. Having said that, 60" long and 2+" wide is over-kill. I would narrow that puppy down to 1 1/2" or so. Ring orientation becomes far less important if you back the bow, but since you have a ring running down the center, I might try and follow that as a guide. Just don't get too narrow, just to stay under the ring. Just thinking out loud, but a sinew backing on your first bow is a big task. Rawhide might be a better option. Easier to get the material, easier to apply...just a thought.
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I second that. Nix on the sinew. Much simpler to back with rawhide and it should resolve the problems you've created by "decrowning" the back. Generally speaking, osage will tolerate decrowning as long as it's done right so rawhide should be the appropriate insurance at this point. If you are having trouble finding some go to the trade blanket and you shouldn't have any trouble getting some.
Scott
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Hmmm yeah I was just looking at the close up photos and noticed there was no ring chased either......was wondering about that.
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Here is an update ... The limbs are 1.5" wide starting from fades to 1/2" at tips. I am applying rawhide when I get it. It will be glued with titebond III,, any tips on application???? And would it be a good idea to wrap a piece of rawhide around handle to reinforce a possible fracture on the belly???
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"Possible fracture on the belly"???? Don't sound good amigo. Can you be more specific? Where, how big, running which direction, when did it show up. Checks on the back, and I'm not saying yours is a check, usually close up under tension, no biggy. Checks on the belly tend to open farther under compression. Not so good. A fracture would indicate, to me, a serious problem.
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The crack(s) have always been there from start. There are two running vertically which at first appeared to be on surface, but now one can be seen on the outside edge of side of the handle. There is one more next it but is entirely in the center . It seems fine now pulling 38#@14",,,should I still rawhide back it???? or should I try to see if I can finish in one piece?
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Everything about that scares me. I have attached 2 drawings (art is not my strong suit, but this is my attempt at 3D) to illustrate my point. I think your handle fades are too thin. Hard to tell for sure from the pics, but it appears that way to me. If you already have cracks in the fades, and you are too thin to boot, it will probably hit you between the eyes at some point. This is assuming a stiff handle design. I will be curious to hear what others have to say, but I think you got a problem. I'm not sure that rawhide will fix it. Again, maybe someone will chime in and offer a different opinion altogether.
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Thanks So much :) I was thinking the same thing the last few weeks but never wanted to see it. I appreciate your info and drawing.