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Main Boards => The Bowyer's Bench => Topic started by: Appalachian Hillbilly on February 21, 2022, 08:43:30 PM
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Got my first set of limbs finished today! Well, almost. Still need to work on tips to get them equal and still need to tiller. Was so anxious to shoot them, I threw on a coat of matte and shot them this evening. One limb takes one more turn than the other to get even tiller, so I know I have one to work on.
Goal was 45 lbs and I hit 43.
This was two .001 tapers and one .001 reverse taper. I want to try some different tapers next.
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I want to explore the effects of different taper amounts on stability at brace height. I braced this one at 8" and it shot very well. At 7" it was too floppy. 6.5" and it would flip flop ....one end a recurve and the other a longbow :biglaugh:
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Lookin good :thumbsup:
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That looks nice the reason those limbs are floppy is because the reflex starts too soon off the wedge I have found you need to stay straight for a bit off the wedge.
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That was what I was thinking as well after playing with it awhile. I will try a power lam to get a little more reinforcement in that area.
I can also move my stop pin in the form. That will give it more straight area and a little less recurve.
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Looking good!! I haven't ventured into takedown bow building just yet...I am sure I will have a go at it at some point. Nicely done!
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Yeah moving the stop pin would be the first thing I would do.
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Good job.
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Do you guys start your limb taper after the fades or before? Shot it quite a bit today and it shoots very well. I strung up all my longbows and compared the limb vertical stability at brace height. This bow at 8" is the least stable but not by much.
I did back out the limb bolts to see what effect the angle change had. When they were out as far as it would allow without binding, the stability increased and was the same as the others. That tells me it likes more angle. The flatter the limb when strung seems to amplify the oil can effect at lower brace heights.
Going to move the stop pin to get a longer straight section and start the limb taper slightly past the fades as compared to before, as I have now. This will stiffen up the center of the limb.
Not ready to make a new form yet. Just trying to lear cause and effect!
Any thoughts?
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Like I said move your butt back first. This will move your string groove also. You will gain stability. Floppy limbs don't mean the bow will shoot bad. Less brace gives more string tension. If you want stability got to reach a happy medium.
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I have been chasing vertical stability for a long time. Keep a lot of notes. Every little change you make will change a lot of the way acts.
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Okay I have a pic. The set on the right are floppy meaning when strung you grab the string and move it top to bottom and the limb tips will flip flop all the reflex out. the bottom set will not move. Both sets are.004 FT. The stable set maybe could get by with less straight but they feel really good after the shot.
Now I have a buddy built a WTT bow with floppy limbs that shot 190 fps. So I guess if you can stand the floppy its okay. Most times floppy comes with bad manners also.
(https://i.imgur.com/k9KhHV7.jpg)
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I went to the shop today and thanks to Kenny M and my new lam sleds, ground some more cores. While I was there, I reworked my tips slightly and did some finish work on my limbs.
Shot them a bunch and they shoot well. Good enough that I might compete with them Saturday.
At 8" brace, I can not make them flip by just pushing on the tips in line with the strings.
I wonder if tip wedges would help as well.
I prepped my form and got another 1 " of straight at the butt end.
Here is the strung profile. Last 2 pics are pushing down on one end and you can see what opposite ends look like when doing this.
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Let us know how the 1 inch helps. Dont think aa tip wedge would do a lot.
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Will do! Going to do 1 thing at a time. I can get maybe 2" more total, then it gets close to the end of the form.
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The best set I have made so far are.
10" of a flat at the bottom
12" wedge
001 taper with a KM superlam
26" long
4" of reflex
There is still a little movement with the shake test.
Crooked Stic how much reflex are you using ???
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I have not really measured my reflex.
Where are you measuring from? I think you want it to start about mid limb. And I think Centaur has a good profile.
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I measure from the table to the string Grove.
I might need a little more of a flat to start with.
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That limb in the pic ought to be pretty solid.
I may go out and measure mine.
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I can move the tips up and down about 1/2" .
I may be getting to fussy about it.
Do you think light pounds makes any difference ? Thay are only 35.
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I have a 35lb RD and it definitely moves easier than my 46lb RD. I do believe that is to be expected some. At brace height it does not flop to one side recurve and one side longbow though. It is pretty stable.
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If you can flip the limb clear over using the string moving it up and down its considered vertically unstable.... But like crooked stick said earlier in this thread, you can sill get faily good performance with a floppy limbed bow.
I had a close friend of mine tell me that Long lean wedges help push the working portion of the limb out further, and tip wedges will determine the length of the working portion. But what determines vertical stability has a lot more to do with the limb shape going into the form. an elliptical shape will be much more stable than a true radius shape. It doesn't need to be a flat spot, but less bend shape through the working portion requires more core depth, and that is what gives you better vertical stability. For adding more reflex at the tip, use a tighter radius or arch..... Heavier draw weights are always more stable. More beef..... Arlo
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Got my first set of limbs finished today! Well, almost. Still need to work on tips to get them equal and still need to tiller. Was so anxious to shoot them, I threw on a coat of matte and shot them this evening. One limb takes one more turn than the other to get even tiller, so I know I have one to work on.
Goal was 45 lbs and I hit 43.
This was two .001 tapers and one .001 reverse taper. I want to try some different tapers next.
Just a friendly heads up on your design..... Using wood overlays look very cool on your limb butts there, but the wood material alone may or may not keep that glass from splitting at the pivot pin hole. Most ILF limbs use a phenolic overlay for good reason..... Ive built quite a few sets without overlays at all and have had to do repairs and overlays after the fact on some of them....
food for thought. Maybe use a piece of stable core material under the wood, or thin phenolic first, then wood. Arlo
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My limb reflex is 4 3/4 measured like yours.
True the limb dose not have to have a straight section but it works. Just more deflex before the reflex starts.
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Thanks Stic
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Thanks for the advice Arlo. I will keep an eye on it. It does have a piece of phenolic added to the bottom . Hopefully that will be enough to reinforce the area around the bolt.