Limb design help

[katalyzt]

Okay I had to take a break on the bow building for a couple months to wrap up another project but I'm back at it now and it looks like I've got some things to figure out.  I've created a limb press mostly based on the Bingham bows press but slightly modified to allow me to press the limb onto the the form rather into the form.  In so doing I now flip the wedge so that the flat pad is against the riser foot and the taper goes up from the riser foot to the tip.  This has resulted in some rather drastic changes that I'm trying to figure out.  The major issue is that that limb seems to hinge at that wedge.  So I thought I'd ask if any of your experienced eyes can help me smooth this curve out.  The riser is 19" with the bow being a total of 60".  The wedge is 1/4" thick 11 1/4" long with a 5 1/4" pad.  My guess is the wedge is just too long but I'm not quite sure by how much. 

[Shredd]

  Yeah... It looks like that wedge goes way out there... I would pull it back a ways... You only need about 2 to 2.5" sticking out there...  Plus you might wanna go with less taper rate on your wedge...  After that and it is still hinging you might want to go with a higher taper rate in your lam...
    I think my wedges are only about an 1/8" thick...  I Think that is a hair on the thin side...  I'm probably gonna go up to .150 to .160 ...

[Mad Max]

Is that a recurve or a R/D?

[Crooked Stic]

Just make your wedge a straight taper. It don't need to be more than .375 at the butt. Kind of a working wedge and it's pretty easy to lengthen or shorten to adjust working limb length.

[katalyzt]

Is that a recurve or a R/D?

takedown recurve is the idea

Thanks for the feedback guys, I'll move forward with a shorter wedge and see if that gets me closer to what I expect to be seeing.

[Mad Max]

A picture of it unbraced would help.
So the recurves are opening up.
The shorter wedge should get it done

[Appalachian Hillbilly]

Personally,  I  like it!

[Shredd]

Personally,  I  like it!

  Do some speed tests on it... Yah never know what yah might got...

[Crooked Stic]

Yeah unbranded pic.

[katalyzt]

Okay I made another pair of limbs.  This time the wedge is 8" in total length with 5.5" being the pad which left 2.5" of wedge sticking off the riser.  I didn't alter the thicknesses of the lams.  The result is a beautiful limb curve and 49#'s at 28".  Here are a couple pics of it longer wedges unbraced and such.  And then a few pics of the new limbs that are hitting the mark.  Thanks for the input guys you saved me quite a bit of trial and error.   

Personally,  I  like it!

  Do some speed tests on it... Yah never know what yah might got...

The wedges barely bent at all so it was SUPER stacky and was pretty tough to get to 28" draw

[Longcruise]

I like the look of that and curious about the speed it will give up.

[katalyzt]

I like the look of that and curious about the speed it will give up.

Sounds like I'll finish up those limbs and see what we get.  It'll be interesting to see how it ends up.  I mean the glass is already spent so might as well.

[Crooked Stic]

If you are calling this a recurve I think you be better off with a little more hook in the tips.  And anything over about 45 lbs. Add .001 forward taper with stablecore to help the limb pull straight..

[Crooked Stic]

If you are calling this a recurve I think you be better off with a little more hook in the tips.  And anything over about 45 lbs. Add .001 forward taper with stablecore to help the limb pull straight..

[katalyzt]

If you are calling this a recurve I think you be better off with a little more hook in the tips.  And anything over about 45 lbs. Add .001 forward taper with stablecore to help the limb pull straight..

I call it a zombie social distancer but for marketing purposes I tend to call it a recurve.  It's pretty much the Bingham Projects limb press plan flipped upside down for easier tapping down and a 19" riser rather than their 21" so I guess that's why I call it a recurve.  But if there's a stricter definition I'd be interested to hear it so I don't look a fool.

I was using Stabil-kore in my limbs but then when I called Bingham Projects to inquire as to why they didn't carry it anymore he said, if I recall correctly, that the Bo-Tuff E glass they sell is super stable laterally as is and it would be superfluous to add the Stabil-Kore.  We'll see I guess.

[Longcruise]

Well,  I'm not in agreement with them ref the Stabilcore.  Probably a few others that would agree.

[Mad Max]

Do you have a belly underlay for the recurve?
You can add a 6" x .030 thick and taper the last 1" to zero and it will stiffen up the recurve some.
This will give you 1 or 2" more string contact on the belly at Brace.

[Crooked Stic]

Stablecore is not the best thing but does help some. It is too bad you can't get two ply carbon twill unfinished on both sides or if the stablecore was a 45 degree lay up.

[Kirkll]

If you test both of those limbs, I think you will find better performance and a better string angle at full draw with the longer wedges because it pushes the working portion out further.  You just need to get rid of the flat spot.

I lay all my TD limbs up with 12” straight taper wedges that are .030 to nothing, and cut the limb butts off about  .5” to 1.5” for medium or long limb lengths.

It may be well worth your trouble trying the longer wedges again in a straight taper. IMO.

As far as limb design goes…. That same form will make a great hybrid long bow limb.  Go with a deeper stack , .003 forward taper , and narrow up the limbs from 1.25” at the riser to 5/8” at the tips. You will see an incredible jump in performance doing this.

Have you got photos of the form?

For a nice recurve design a bit more hook, using tip wedges to keep them more static is the ticket. But… once you start using an aggressive hook you need to cut that forward taper down to .001 or even a par like crooked stick recommended, or they start going sideways on you. And use stable core under the wedge on the belly side.

The difference between core tough and stable core is night and day. Core tough is .030 thickness and twice the weight. Bingham’s doesn’t sell stable core, so they won’t recommend it.

.02 cents worth.    Kirk

[Crooked Stic]

Kirk you say .030 to .000 in 12 in. Or that a typo.
I have went with the st. Taper  in my curve but it is more like .300 to .000 in 10.5 in.