Primitive Archer
Main Discussion Area => Bows => Topic started by: Bluekable on September 04, 2013, 08:50:58 am
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Hi all,
Firstly, as this is my first post, I would like to thank you all for the effort you put in to sharing your knowledge so freely. As a beginner bowyer I have found so much information in this forum and really appreciate all the support you all offer.
I have reached a stage in my first bow where I believe it will benefit me to straighten out a bend and possibly even some twist in order to move on to tillering. I have posted a picture of the bow and as you can see it is quite straight from bottom to handle, after which it begins a gradual bend to the right getting most pronounced (i think) about 5 inches after the handle.
My hope was to bend the bow in one place, at the five inch mark above the handle, and hope that the one bend would be enough to straighten it.
If not, I would straighten the top arm relative to itself and then do a second bend at the handle to bring this (now straight) arm into alignment with the bottom arm.
I tried steaming the bow at this "five inch above handle" mark,I left the bow over the pot for about an hour. When I tried to bend it however it didn't feel anywhere near as pliable as I had hoped. I gave it one more shot, adjusting my pot steaming system to make sure the steam was more focused on the area I wanted to bend but again to no avail.
I have read that for each inch of wood, one should steam it for about an hour. Because my bow is about an inch in thickness this lead me to believe I should steam it for one hour. However my bend is not vertical ie. in the direction of the inch thickness but rather horizontal, which has a thickness as you can see of about two inches.
So my questions.
A.) Should I be steaming it for longer?
B.) Do you think I will get away with one bend or will I need to go with my second option for straightening the bow out.
C.) If, after the bend is straightened, I still need to straighten some propeller like twist, will the same steaming rules apply?
All advice is welcome guys.
Thanks.
Shane.
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Sorry guys my photo file is too large to post, will post one as soon as I can find a way to shrink it.
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Are you on a pc or Mac?
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An inch thick limb 2 inches wide is a lot of wood to bend. Don't know what wood you are working with, but get the limbs bending a bit at floor tiller and try it again. Cant tell you how thick, but 5/8" thick is near half as much wood. Much easier to bend. One bend might be fine, might need to straighten again. Don't worry about the prop twist unless it is fairly severe.
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Go to properties on your camera and set it to 640x480
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Hey guys, here's another attempt at posting a picture of the bend.
Shane
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What is you system for straitening that beast :)
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Shane, as SLIMBOB mentioned, I don't usually try to do any bending until after floor tillering or even after long string tillering. I haven't steamed a bow in years. I use the heat gun.
With a stave like that I leave the nocks and inch wide and the handle wide until I string the bow and even after. That way I can make minor corrections to track the string. I can cut one side of the nock deeper to bring the string over towards center and I can shape the handle accordingly to track the string.
Jawge
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I might try that one in stages with a heat gun as Jawge stated. Clamp, bend a little, let it cool, and the move up the limb and repeat. And repeat again until it tracks straight. Hackberry???
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I have one or two staves like that cowering in a dark corner of my shop.
With the limited time I have for bow making these days due to work and a young family I try to opt for wood that needs less work to get to a basic profile. There are enough things to go wrong with a bow without a massive tip deflection like that. Moving a limb flat against its plane like that is hard work to say the least. If you are brave enough and have the time then try to spread the bend out over a large area of the limb, then when it wont budge any more take the rest our at the handle.
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Thats a lot of bend for one limb, you could always move that limb a little and then move the other limb in the opposite direction until you get the string to track through the middle of the handle. That way you only have to move the limb half as much.
Grady
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Id steam the center 12" for no less than and hour and correct it there. Tweak the limb itself later with dry heat.
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Like that even better.
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Just a question, I've only just started steaming and I don't know much. Because he's already necked down the top and bottom of the handle isn't that going to concentrate the bend into those two areas and maybe break? :-\
Don
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Don the key to success depends on where the over bend blocks are placed and where you place the clamps. That handle area is still robust and will take a lot pressure and bending. Moving the fade on that limb 3/4" at the handle will move it a bunch more at the tip.
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Thanks, I hope I didn't put any doubt in Slimbob's mind. I didn't mean to.
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No prob Don. This is a problem to solve on a couple of levels. A person without much experience trying to bend a problem stave sideways, a bunch. Best approach in my mind is to seek opinions and go with the one that makes the most sense. I probably would just use a heat gun to bend the handle, but I know what I can get away with. I think PD has the best call here.
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Thanks a lot to everyone for your input.
I agree SLIMBOB, I feel that PD's suggestion feels best and I will give it a try.
Just for added info, the stave was from (I am 99% sure) a China Berry, which is a tree that we commonly call Saringa in South Africa - even though its not really Saringa. We have LOADS of them growing over here and while I was picking some Mulbury, Maple and Stinkwood trees to cut for seasoning I came across an already dried out log of Saringa in my neighbor's wood stock. Wanting to get my hands dirty as quickly as possible, and hoping to get some practice in before trying anything out on the Mulberry and Stinkwood staves I have seasoning, I decided to give this stave a shot.
As a result I wont be all that fussed if it doesn't turn out that well but I would like to give it my best effort in the hope that it does.
Alongside all this I must mention JAWGE and SLIMBOB, that the bend (And possibly the Prop Twist compunds this) causes the bow to twist whenever I try to floor tiller it. I get some bend but I have to counter the twist quite firmly with my hand thats holding the handle. Fot this reason I felt that it would be better to try get the bow quite straight (Bend or Twist or even Both if required) before tillering so that I could floor tiller with a bit more comfort. All this being said I have no experience in tillering letalone floor tillering and as such this is all intuitive reasoning. Any suggestions on whether I do or do not need a straight bow for floor tillering will be appreciated.
Again, thanks for all the help guys. Will keep you updated if things work out.
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You will get some differences in opinion on floor tillering. Some will floor tiller till the bow is nearly complete. I floor tiller only to get the limbs bending evenly with each other 4 - 6 inches or so, then I get a string on it. I don't have to fight what you described as long as some others might. As a rule, I don't worry with prop twist. Some of it will straighten out once I have it finished, and what remains is of little consequence. 90 degrees is too much, but half that I can live with. Some people just will not have it, and remove it all. The problem you will have without a proper setup for such a task, is that you will straighten the limb laterally and then take the twist out or visa versa. Either way the first bend will straighten back out as you heat for the second. Heating and bending both moves at the same time is required. If you can do that, great. If not, straighten the limb laterally and see if the prop twist works itself out somewhat as you tiller. That's what I would do. See what else comes along here. Good luck.