Limb Performance

[buckeyebowhunter]

Hello guys,

Been a little while since I posted but I've built a few bows in the meantime. I feel like each riser that I've done has gotten better. But my limbs seem to have plateaued as far as their performance is concerned. My main concern is that I can't seem to eliminate the "stack" at the tail end of the draw. They just don't seem to be smooth drawing limbs compared to some of the bows that I own. For example my 45# limbs seem heavier than my 48# black widow limbs. I know I'm comparing a top of the line bow to amateur limbs but I was hoping you guys may have some tricks I can try or ideas that may give me a place to start at improving the performance of the limbs.

Just some background on the bows I've been building. So far I have only built takedown recurves, and for the most part I use the bingham limb stack formulas. The limb profile of my form is also from binghams. I've mostly been using their actionwood for my limb cores, but also built a bow with elm, and walnut.

Thanks!

[monterey]

A couple full draw pics would be good.

[Shredd]

If you want help you need to supply all the details and pics of your bow... Unstrung, at brace and at 28" draw... And maybe a pic when the string leaves the limbs and what draw length it does...

[buckeyebowhunter]

Ok guys gimme a sec, still at work. 

[buckeyebowhunter]

These are the best I can do for now. No way to get a full draw pic. 

[buckeyebowhunter]

[buckeyebowhunter]

[buckeyebowhunter]

Obviously this bow is not yet finished but the specs are
17" riser, bow is about 60" unstrung and right now pulling about 46# @28. The limb stack is ULS .043, parallel .050, and taper .100

[Mad Max]

Whats the brace height?
Binghams limbs are 1-3/4" or 2" wide, what one do you have?

[buckeyebowhunter]

It's braced at about 7 an a quarter. Started with two inch limbs. But after shaping and tillering they're probably 1.75".

[Shredd]

I am assuming it takes a 57" string??  What is the distance between the ends of the wedges (fades)??  Are the other bows that you are comparing them to the same length??  Do you have power lams in there??  What are the angle of your riser pads?? Are you curves static or working???  Full draw pic would help...  Also in that side profile you chopped off the ends of your bow...  Would like to see a full side profile shot... Full draw pic is really important... 26 1/4" tiller stick...   Be careful...

   I am not a recurve guy but my first impression is your geometry might be off...  Them limbs look raked back really far and the hooks appear big...  A 17" riser and what appears to be 21 - 23" from fade to fade... There is very little room for the limbs to work... I could possibly see why you are stacking...  Then again I am not experienced with recurves...

   Did you lay your bow up against your other bows and compare their shapes??

   

[buckeyebowhunter]

Shredd, you're going to have to school me on "power lams" I've heard the term thrown around but don't fully understand. Also will measure the wedge to the fades in the morning. Riser pad angle is 21 degrees. I cannot hardly compare it by profile with my widow because the design is belly mounted limbs. I am simply comparing the feel on how they draw.

[Shredd]

Somebody correct me if I am wrong but a belly mounted limb has a big advantage on a shorter bow...

[buckeyebowhunter]

You guys are gonna have to walk me through the geometry on this stuff,  an take it easy on me I'm an art guy not a math guy

[buckeyebowhunter]

Wedges are roughly 8" from end to fade.

[Crooked Stic]

First of all if you are doing the Bingham design and using the tapers they say and their pad angles and form shape you should be good. Have you done a FDC to see how much you are gaining per in. you talking stacking at 28 in. or where at? Heavier bow will gain more per in.

[Shredd]

Wedges are roughly 8" from end to fade.

   No...  I need to know the distance between the two fades...  From fade tip to tip...  As I said it looks like 21 to 23"...

[Crooked Stic]

There is enough deflex in that riser that it can get buy with a short working limb. If you built it by Bingham specs.

[Mad Max]

There is enough deflex in that riser that it can get buy with a short working limb. If you built it by Bingham specs.

x2------ Could just be the design is not as smooth draw as the widow.

Riser should be 19" for the 58/60/62"
21" for the 64/66/68"

[buckeyebowhunter]

Max you are correct about the bingham designs with limb length. However, I wanted a 17" riser. So I took their riser template and using adobe shrunk it keeeping the pad angles the same but just a shorter smaller profile riser. For this particular bow, I used their 62" limb formula. And this bow does seem to draw better than the first few I made using their 19" riser and 62" limbs. I just figured there may be something I could do differently or modify to make a smoother draw.