Primitive Archer
Main Discussion Area => Bows => Topic started by: DC on September 17, 2017, 12:28:41 pm
-
I'm working my way though this. It's going well. When I identify an area that is taking set(call it a hinge) I believe I'm supposed to weaken the rest of the limb to match that spot. Do I always have to weaken both sides of the "hinge" or is there times when one side will do? You can see where the limb is bending away from the line at the red arrow. Can I just scrape from the red arrow toward the handle(on the right)?
-
DC, are you referring to Badgers method of "no set"? I believe he uses the scale to detect set before it becomes visible.
-
I am but I don't see how it can detect set before it's visible. Once the damage is done the bow isn't going to return as far.
-
well, technically you are correct. The method is intended to minimize the cell compaction, that precedes visible set.
-
when you wiegh the bow like Bader does, it can detect set before it is visable
-
If it's invisible how are you supposed to know where to correct it?
-
DC,
now that you have made the distinction that set is not invisible, perhaps we should call it excess strain?
As to where the invisible excess strain is located, I would suspect anywhere there is excess bend.
perhaps this is where the badgering technique comes in?
http://www.primitivearcher.com/smf/index.php/topic,61452.0.html
-
Willie has it, knowing that some excess strain is happening and knowing where to find it is another issue. If you are one of those with a real good eye it helps a lot but just stepping back and carefully examining it for stiff spots and spots bending too much is the best I can come up with. For laminated bows or very straight staves a gizmo can be a big help. It is time consuming and kind of a pain but I really like the results.
-
I have found that if a limb has a weak spot, and you are not to draw length yet, you can actually scrape the opposite limb to take more of the bend, relasing strain in the weak spot on your other limb. This makes the entire limb with the bad spot the stiffer limb and not just taking care of the one spot. Then tiller like normal, bring the entire limb around to match, just being careful of weak spots.
-
Hold on, a bow can bend before it starts to take set. I've found that if I don't bend it past the intended weight, measuring the weight on each pull, I can simply tiller as I always would... taking wood off a little bit at a time until the bend is even. Hopefully I don't develop a hinge cause I'm going slow enough and if I do, I leave that section alone and either scrape next to it, or on the opposite limb (like sleek was saying).
If I do the above and it still takes set, there was something wrong about my design. Am I getting this right?
-
The thing is, if I can't find the weak spot I'm dead in the water. The bow has taken 1/8" set. I think the weak spot may be here, so I scrape a bit and put it back on the tree. Now I have to redo the benchmark and start again. If I missed the weak spot now I have 1/4" of set. Still not enough to see(at least for me) so it continues. This is where I am now. I have the bow out to 40#@ 24". Almost there but it takes a little set every time on the tree. Still only about 1 1/2" but enough to pee me off. Now I'm starting to doubt myself. I had two primo Yew staves. One in the warm box for six months and the other leaning against the wall in the shop. Did I mix them up? Crap, I don't know. I'm heat treating it now. Thing is, it's going to be a great bow. A piece of Yew like that would morph into a good bow on it's own. Anyway if anyone sees a flaw in my process please point it out.
-
I take it your intended weight is 40#. If it were me and I never pulled past 40, I would be thinking that it should have been wider or longer. And like Badger says, some set often cannot be avoided.
You could always flip the tips a little to compensate for that 1/8. :)
-
Or try what I have been experimenting with. If a bow wants to take an inch of set, heat treat the set out, then deflex the fades to take the tips down 1 inch. This restores the crushed fibers with heat, and unloads the bow of that 1 inch if stress it couldnt handle. Yes, you loose that one inch of draw, but gain effeciency in not having crushed fibers trying to do work.
-
I take it your intended weight is 40#. If it were me and I never pulled past 40, I would be thinking that it should have been wider or longer. And like Badger says, some set often cannot be avoided.
You could always flip the tips a little to compensate for that 1/8. :)
Yeah 40#. 68" long and 1 1/2" wide. For Yew that's way overbuilt, I think.
-
Dude, you shouldnt have any set yet unless you have damp wood, a bad piece thats mostly early wood, or its still damp. Assuming a correct tiller. Can we get a tree pic with it bending?
-
I just heat treated one limb and was just heading out to do the other so it will be a day or so before I bend it again.
-
Good luck. Your bows always look great so I'm sure this one will turn out just fine. ;)
-
dont panic,, the bow is still in there, I bet after the heat treating it will be right on,, (=)
-
Mark a big x where the hinge is. Remove wood from both sides of the hinge leaving it alone. Exercise at short pulls until the hinge is gone.
Yes, retiller the other limb to match.
The best way to fix a hinge is to not get one. Learn to back away from aggressive wood removal tools and use those that just remove small amounts. Check tiller frequently.
DC, did I read on here this is your first? If yes, IMHO just concentrate on getting a bow and don't worry about set.
Jawge
-
Mark a big x where the hinge is. Remove wood from both sides of the hinge leaving it alone. Exercise at short pulls until the hinge is gone.
Yes, retiller the other limb to match.
The best way to fix a hinge is to not get one. Learn to back away from aggressive wood removal tools and use those that just remove small amounts. Check tiller frequently.
DC, did I read on here this is your first? If yes, IMHO just concentrate on getting a bow and don't worry about set.
Jawge
I don't know where the weak spot/hinge is. That's the problem. Look at the picture at the beginning of the thread.
-
I cant tell what part of the bow that is from the pic,,
can we see the whole bow,,
-
That's the middle of the limb, tip on the left. It's been heat treated now and it doesn't look like that any more so there's no point taking a picture.
-
DC, respectfully but honestly, if you cannot tell if and where the stave is hinged then you should not worry about set. Leave that worry for bow #12 or so.
A hinge is where the stave bends too much in one spot in relation to the rest of the limb.
I cannot tell what is going on from that picture.
There are buildalongs on my site.
http://traditionalarchery101.com
Jawge
-
Don has made more than 12 bows jawge. Not his first by far. Cheers- Brendan
-
Oh ok. Sorry. Thanks. Jawge
-
ok from what I can tell in the pic,, that is the spot that might be a bit thin,,
just a suggestion,, take wood of the outers and toward the handle before you remove any wood there,,,
even if you heat treated,, ok but if that spot of the taper is too thin,, it might be a problem,, or is indicating that the limbs are not bending even,,
if we could see the bend of the bow, ,it would be easier to tell where it might be over stressed,,
the tiller would indicate if that part of the bow was working too hard in relation to the rest of the limb,,
but at this point I am really guessing with not enough info,,
-
Also while we're at this, the back of a stave is rarely even. It can go from flat to crowned to concave. How do your fingers and brain deal with that? Does that get into that other elusive talent, judgement call.
Pearly wrote "close your eyes", and I might add that spending a few minutes gauging the suspect area with multiple passes will give you an intuitive idea where the thin spot is.
-
Here ya go. 43@26" Shot it a half dozen times. Robin Hooded(wd?) the third shot. Shoots nice and I still have to reduce the tips a bit. After heat treating and a little tillering I ended up with about 1/4" of reflex. More than happy with that. I'll tart it up a bit and post it later.
-
Looks like you got her all figured out.
I admit I am nit pickin here, but is your left limb not as bent as the right? The bend looks great on both, but maybe its shafow or something makung it look ever so slightly off?
-
Here's the unbraced pic. I think the left limb is a touch stiffer. It's the bottom limb. There is also a bit of a whoop-de-do mid-limb that makes a bit of a flat spot in the full draw. That's my story and I'm stickin' with it ;D ;D
-
thats looking good and I wouldnt mess with it, ,congrats,,
but I do see that deflexed part on the left limb,, seems a little thick.. like it tricked your eye, ,cause its looks bent,,,,
but the way the bow is holding,, please dont touch it,, :)
-
I measured it and it's thicker there by about .020". It always amazes me that you guys can spot things in a picture that I can't see when I'm holding it in my hands.