Primitive Archer
Main Discussion Area => Bows => Topic started by: gfugal on November 17, 2016, 04:06:38 pm
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So I have a staff that has a very nice natural reflex at the handle, the only problem is that it aslo twists slightly to one side. If you hold the handle straight forward it looks like the tips twist to one direction, but both the top and bottom twist in the same direction offesting the string pull. I have a steambox I made and have reflexed limbs before but never tried fixing a twist in a handle. I'm concerned about how much time it's going to take to clamp both tips down and make some kind of tourque lever to twist the handle. How long do you have before the wood starts to set after you heat it.
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i usually try to orientate the handel toward the string with the way I shape it,, maybe thats not possible with y :)our issue,, but think about it,, :)
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I always try to make all adjustments within 30 seconds, 60 at the absolute most. TBB v. 3 has good info in "Bending Wood" chapter.
A picture would be helpful, but based on your description, I would consider clamping the bow belly up on one side of the handle to a slightly curved jig that matches the bows natural reflex, placing that over steam covered with foil, and after a while (how long depends on the thickness of the handle) clamping the other side of the handle to remove the twist. If that doesn't correct the string pull at the tips, use dry heat at the outer limbs from there.
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Do a dry run first. Do a complete setup. Have all the clamps adjusted to the length you need and everything right at hand. Doing a couple of practice runs can't hurt.
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Unfortunately I'm past the shaping stage. I originally cut out the rough shape by eye and thought it was straight but when I lined it up with string and everything it was off center. I had to cut the limb width in effort to correct it, like mentioned in the twisting limb forurm, but I can't cut off much more since it's about 1.5" on the handle and close to 0.5" at the tips. nock to nock now lines up pretty well, with the handle closely centerd, but due to its twist it causes a tourque when I try do any bending.
60 seconds doesn't give me a lite of time to work :(. I'll see if I can time myself and keep it under that time. I probably should buy some clamps that I don't have to twist to tighten. Maybe I could also keep the tourque lever lashed to the handle while I steam it saving me the time of doing that. How long do you think it will take to set. Will I have to hold the tourque for a couple of minutes or does it take hours to set? Last time I did recurve tips I just clamped it and left it for a day so I have no idea.
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I will try to include a photo as soon as I can, but it may have to wait till tomorrow. A picture will probably help since the subject is a little misleading. The twist isn't actually in the handle but the limbs. It's just the tips of the limbs are parallel with each other and the handle is the odd thing out. Almost like someone clamped a bow down at both the points and then twisted the handle (hence why I want to do that with heat to twist it back).
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I probably should buy some clamps that I don't have to twist to tighten. Maybe I could also keep the tourque lever lashed to the handle while I steam it saving me the time of doing that. How long do you think it will take to set. Will I have to hold the tourque for a couple of minutes or does it take hours to set? Last time I did recurve tips I just clamped it and left it for a day so I have no idea.
If you have your clamps adjusted ahead of time it only takes a few turns. You have to leave the torque lever on for at least and hour. Most people hang a gallon of water on the end of the lever. Put a stool or something under it to limit how much it twists. When you are heat bending something always go a little past where you want it to allow for spring back. Yes lash your lever to the stave. Do everything you can ahead of time. You will be amazed at how much you can accomplish it a minute. If you get everything set up right you'l have time to start a beer before your minute is up ;)
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Here's the pictures showing the staff with its natural reflex and unfortunate twist. As you can see its not much of a twist but its sure causing some problems.
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This is my proposed method of setup. I can see now that The handle isn't in line as a thought either. I will see if I can somehow bring it to the right while I'm torquing it.
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Before I make adjustments I like to get a bow to low brace unless it is completely out of whack. A little twist in a wood bow isn't necessarily a bad thing so I like to be sure it is a problem before I put in the extra work.
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+1 :)
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yes definitely +1 what Pat said,,
i think if you get it strung ,, you can slightly shape the handle toward the string,, if you have to bend it,,, then do so,, but it may not be as bad as you think once braced and bow reveals it true alignent,,
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So my proposed method did not work! The lever didn't have any integrity after steaming and the lashings were nowhere good enough under forces that great. The lever bent and the lashing twisted, so I just tried twisting it with my hand and holding it. It took a little of the twist out but not much, so I tried again, but this time just clamped it down onto a level surface. That worked enough to allow me to brace it with some tillering. Included are the photos of it braced. You can see in the first two how the string pulls to one side. Should I continue tillering it by taking wood off the strong side, or should I see if I can fix it with a form built to counteract the twist. It has taken a little bit of set since being braced.
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Your string alignment is good. I'm a little concerned about the spot where the bow, your recliner and the floor meet. It looks to be hinging there, may be camera angle.
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work on getting the bow to bend even, dont worry about the handle it is fine,, shoot the arrow off the side that the string going too,, you tips are wide enough,, if you want to move the string more toward the center,, then move the nocks that way,, getting the bow to bend even is the main thing right now,,
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work on getting the bow to bend even, dont worry about the handle it is fine,, shoot the arrow off the side that the string going too,, you tips are wide enough,, if you want to move the string more toward the center,, then move the nocks that way,, getting the bow to bend even is the main thing right now,,
+1
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Yeah, there's some real work that still needs to go into it. It is kinking right below the handle at that spot, It's also very stiff in the upper limb right above the handle. I think I'm going to just tiller as is. I was hoping that I could get 50# out of it, hence why I was thinking of recurve & reflexing it some more but it's already taking set. I'm surprised that it has any string follow at all since 1) it was originally reflexed, and 2) I haven't gotten it anywhere near full draw yer. Have you guys had that happen, and if so were you still able to get a strong bow? My situation might be different since it's such a short bow--43" nock to nock.
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Your bow is really short at 43 inches, and with a stiff handle, your limbs are even shorter. You can minimize the stiff handle by shortening the fades some, but be careful not to create a hinge at the end of the fade. If your next stave is short like that, make it bend through the handle.
For a beginner, a good rule of thumb is that a self bow can be drawn to 1/2 the working limb length. So a 48 inch bow that bends in the handle can be drawn to 24 inches. Your bow is 43 inches minus the stiff handle-say about 37 inches. This means it can draw to about 18 inches. As you gain more skill and find better wood, you can break this rule, but even the finest bowyer would have trouble getting that to draw 28 inches.
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How narrow is the narrowest part of the bow? How tall are you? It may not be too late to make it bend in the handle.
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My first bow was super short like 38" NTN. I somehow managed to get it to a draw length of 23 inches with a working handle and sinew backing. However, it was disappointingly week at 20#. In an attempt to raise its weight I applied another layer of sinew. It did get stronger but, without thinking of rechecking the tiller, I drew it to full draw and it broke on me.
My second bow is 45" NTN recurve with a non-working handle. I am in the process of finishing it up at a 26" draw length; just got to wait for the second layer of sinew to dry and this time double check its tiller. I'm hoping to get it above 30# but It was getting close to its limit before the second layer with about 1/2" - 1" string follow and major chrysalis.
As you can tell I have a trend for making short week bows. I was hoping to get something stronger but probably not. This is due partially to not having long billets to make a longbow, and partially due to me being a sucker for short bows. Your probably right and I should resign to the fact that I probably won't get anything stronger than 40# unless I do a horn bow.
If I added extended tips to it do any of you know if that increases the draw length? It probably would increase the strain so I might not see it make it to that draw length if it does.
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Sounds like your first bow broke because it was too short. Sounds like your second bow failed (chrysals) because it was too short. How many super short bows do you want to break before you decide that you want to make one that actually works? I commend your enthusiasm and hard work, but the reality is that if you want a working 50 lb bow, you will want to make it longer. Later in your career you can start breaking the rules, but for now I reccomend a design that will have a higher chance of success.
Splicing in stiff tips would add a little draw length, but reduce draw weight
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Why don't you splice tow of those 40 inch billets together and make a stave of a decent length? Cheers- Brendan
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One limb seems to have a hinge(lower limb-just off the handle) and the other is whip tillered (bending too much-around mid limb on).
I'd unstring it and attempt to straighten out those problems with the long string.
Did you skip that step?
Anyway, here's how I remove excessive twisting.
http://traditionalarchery101.com/fixtwist.html
Jawge
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I think I missed something, I did not know your goal was 28 inches with a 43 inch bow,,
20 inches with a working handle would be reasonable draw,,
if you want a 50# bow from that you would need to sinew back it,,flip the tips a bit,,
and it might go 21 or 22 inches,, make the handle work,, and it might go a bit further,,
but the sinew backing will increase your odds of getting a heavier bow....
if you like short bows, dont be discouraged, they shoot well and are fun and effective as a hunting bow as well,,