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Main Boards => The Bowyer's Bench => Topic started by: buddyb on February 16, 2024, 12:28:55 AM

Title: Recurve limb alignment question
Post by: buddyb on February 16, 2024, 12:28:55 AM
Its been a few years since I built a bow so I'm working on  recurve take down and a take down long bow. If the limb bends to the right when strung do you remove a little off the right side of the limb?

Buddy
Title: Re: Recurve limb alignment question
Post by: Crooked Stic on February 16, 2024, 08:22:23 AM
The best way for me is leave the tips wide and file witchever string groove deeper that brings the string to center.. then equal your tip profile.  I have never had much luck with removing material off the strong side.
Title: Re: Recurve limb alignment question
Post by: buddyb on February 16, 2024, 09:57:47 AM
Thanks Mike I thought about that too.
Title: Re: Recurve limb alignment question
Post by: Crooked Stic on February 16, 2024, 10:12:55 AM
Also aa good idea to use the stablecore. Lately I been getting cheap China made carbon .019 twill and putting it under the veneer on the front of the Limb.
Title: Re: Recurve limb alignment question
Post by: buddyb on February 16, 2024, 10:28:46 AM
I checked my records and I did put stabilcore in these limbs. I glued them up in 2020 lol the same for the longbow limbs.
Title: Re: Recurve limb alignment question
Post by: Kirkll on February 16, 2024, 11:54:44 AM
With Recurve limbs it’s a balancing act. The more aggressive the hook you have determines how far out on the hook you can put your string notches before it starts going sideways. Of course  the shape of your limb, limb pad angle, and taper rates can all effect the stability. 

First and foremost is getting those limbs mounted straight , and like Mike said, leave the tips wide so you can adjust for alignment. You do not get very much help trying to sand the edges of the limbs.

I think  You’ll find the thickness of the limbs at the base of the curl is the key to stability.  Stable core helps, and bias weave carbon can help too. The best support I’ve got from stable core to date now was using it right under the glass on the back of the limbs. Same with that twill carbon, and even more stable putting it directly on the back……. Of course the down side to carbon backed limbs is that you cannot sand it to adjust tiller or draw weight.

Good luck on your recurve rabbit hole…. It’s a deep one full of mystery.  :biglaugh:
Title: Re: Recurve limb alignment question
Post by: Stagmitis on February 16, 2024, 06:18:02 PM
Buddy,

To answer your question looking from the belly side of the bow if the limb bends to the right away from the shelf you want to sand the belly glass on the left side (opposite of bend) equally to correct.  Make sure to identify whether only one limb is
Bending or both in the same direction. If they are great. If not then you need equal passes in opposing direction.
Title: Re: Recurve limb alignment question
Post by: buddyb on February 16, 2024, 07:17:10 PM
Thanks guys.

Kirk I did put the stabil core right next to the back glass. I'm hoping for a bow in the low 40 pound range..
Title: Re: Recurve limb alignment question
Post by: Crooked Stic on February 16, 2024, 07:51:27 PM
Another thing if you grind your own lams you want to be sure your side to side thickness in dead on.
Title: Re: Recurve limb alignment question
Post by: buddyb on February 16, 2024, 08:41:52 PM
I get my lams from Kenny or Binghams. I still have a green riser block from you to use too.
Title: Re: Recurve limb alignment question
Post by: Crooked Stic on February 16, 2024, 10:04:51 PM
That green would look good with a black I beam.
Title: Re: Recurve limb alignment question
Post by: Mad Max on February 16, 2024, 11:04:40 PM
 I'm not sure it would work but here it is. :dunno:
String grove depth could work
(https://i.imgur.com/Y1FPzYs.jpg)

I think the bow limb is off center, lam thickness from side to side like stic said, or the glue up form is not square to the sides.
Title: Re: Recurve limb alignment question
Post by: buddyb on February 16, 2024, 11:25:34 PM
Thanks Mark that helps a lot.

Mike I do have a block of black as well and black and green would look good. I need to finish the two bows I have started first lol.
Title: Re: Recurve limb alignment question
Post by: kennym on February 17, 2024, 07:55:27 AM
Don't think anyone mentioned, on a TD if the limb pads aren't square to side of riser block, there is a built in twist. Especially on a recurve bow...
Title: Re: Recurve limb alignment question
Post by: Mad Max on February 17, 2024, 08:17:49 AM
Don't think anyone mentioned, on a TD if the limb pads aren't square to side of riser block, there is a built in twist. Especially on a recurve bow...

Yep
Title: Re: Recurve limb alignment question
Post by: jess stuart on February 17, 2024, 09:35:29 AM
I have found tillering blocks to really help too.
Title: Re: Recurve limb alignment question
Post by: Kirkll on February 17, 2024, 10:32:33 AM
There is a lot to that statement about checking your stack thickness on both sides prior to lay up. Even taking great care flipping your lams as you are grinding them, you can get .002-.003 off  on one lam alone.  Multiply that by 4 and you will have a weaker limb on one side.

Often times just flipping selected lams over in the stack can even things up prior to lay up.

I would highly recommend wider tips and deeping the tip notches over sanding glass, or sanding the width profile. Sanding glass thickness unevenly like Stagmitis suggested is dicey……While it could help you a bit, You can easily ruin a limb doing that if you are not very careful.    Been there , done that…. I use the tee shirt as a thinner rag now….. Kirk
Title: Re: Recurve limb alignment question
Post by: Crooked Stic on February 17, 2024, 11:03:48 AM
I have eliminated limb pad cutting sleds by making profiling jigsfor riser fronts. This does away with everything have to be perfectly square. It don't mean you can be off a mile from square but everything end to end is on the same plane.
 [ You are not allowed to view attachments ]
Title: Re: Recurve limb alignment question
Post by: buddyb on February 17, 2024, 11:44:56 AM
I check my limb pads for square before shaping so thats good lol.

Here is the bow. I have more of a hook than binghams plans.
Title: Re: Recurve limb alignment question
Post by: Mad Max on February 17, 2024, 12:40:46 PM
I will say this again over the years.

I did Tool & Die and Machine work for many years.
Make every part as close to perfect threw the whole process and you will be good. :jumper:

I think you can be off a little easer on most long bow.

Your glue up form is the most important part of the process. :thumbsup:
Title: Re: Recurve limb alignment question
Post by: jess stuart on February 17, 2024, 12:43:16 PM
Nice looking riser.  Years ago I began adding hook to Binghams takedown, you can go to far very easily especially limbs with lower draw weights. I found out the hard way.
Title: Re: Recurve limb alignment question
Post by: Crooked Stic on February 17, 2024, 01:20:55 PM
True Max a  stack of tolerances don't work   That limb gots lots of preload.
Title: Re: Recurve limb alignment question
Post by: buddyb on February 17, 2024, 05:31:47 PM
Absolutely Max if its built in wrong you might as well start over.

Thanks Jess its laminated walnut strips and hickory accents.

I've built several bows with this pattern, its just been a few years. It may be the last recurve I build and concentrate on take down longbows. My longbow is Kenny's design with a few riser changes.