A little trouble understanding the physics of this ...

[kenboonejr]

Still working on my first Bingham Projects take down recurve.  I have both the limbs trimmed down to size, grooves cut for the strings and was able to put the string on the bow.  So at first glance it doesn't look too bad at all.  At this point I am supposed to use an 18" stick and put it between string and riser so I can detect any limb twist.  Turns out one of the limbs has a little twist.  It is not much but it is there.  In my case if I am standing in line with the bow and looking directly at the tip that has the twist, basically the left side of the limb as I am facing it, is slightly lower than the right side of the limb, which make the tip point slightly to the right.  Now the instructions say to note the way the tip is facing (right side) and on that side of the bow, cut the string groove in another 1/8" deep and then take about 1/8" off of that side of the limb from the tip about half way to where the limb starts to taper.

This is what I don't understand.  It seems to me if the right side is the side that is higher up if you will than the left side, that would mean the left side is stiffer than the right side - that is why the right side is bending more toward the string than the left.  So in my thinking (which I must be wrong and why I am asking the question) you would want to take material off the left side to make that side weaker to equal the right side.

Just trying to understand how this works here?  What am I not getting?
Thanks,

[Mad Max]

To hard to tell you, just trust it.
Why is the sky blue

Don't forget, this is the belly

[kenboonejr]

Mad Max - Okay I saw that diagram elsewhere and that diagram makes sense to me.  What the bingham video shows is that you you make the knock deeper on the side it is twisted  you sand that same side that you cut the knock deeper on.  Then I found that diagram you posted which makes sense to me and then I thought I was mistaken what I saw in the instruction video.  But then the guy in the video sanded the same side that he cut the groove deeper on and that is what they said.  That is why I was confused about the whole thing.

[Mad Max]

 

[Shredd]

  An 1/8" is a lot...  Try a 1/32 or 1/16" and work your way up...

I don't think of the limb, which side is stronger... I think of it as, where do I need my string to pull nice and center on the limbs...

[Jeff Freeman]

I'm going to follow this. I just received a roughed-out recurve, from a fellow tread gang guy and it needs a little straightened up. I'm used to doing longbows. Those are a lot easier, a lot easier. JF

[kenboonejr]

I was thinking 1/8" was a lot too.  I don't have a lot of experience at this - well this is my first fiberglass laminated bow - but I have made a board bow.  I learned on that one real quick, that you can take off too much too fast and then you end up with a bow for your kids instead of you!  And thats okay too

Anyway, last night I tried to do it the way the video said and I was just taking a little at a time off and it didn't seem to have an effect on it.  And then I saw a post on WoookiesWords blog that showed that same diagram.  And honestly that made sense to me as why that would fix my problem.  So before I started on it I called and talked to Elmont a little bit and he went over several things with me that could cause limb twist before I did anything else.  I felt confident that my drilled holes were in perfect alignment so I didn't think that was it and I had my nock string grooves pretty even so didn't think that was it.  And he said just eyeball it and see where you think the limb might be bigger on one side.

So after talking with him and yall's input, I did see where I needed to work on the nock groove and make it a little deeper on the right side.  Then I hit the left side of the limb on the sander about mid limb to limb tip and then put everything back together.  This time I closed the gap.  Took it apart and hit the left side of the limb with the sander again and put it back together and everything was spot on!

I then filed my string grooves into the belly and pulled off the masking tape which I have been waiting to do for quite some time.

I have been sick all week man too and just itching to get at it.  Next I will work on the limb tips.

Here is a pic of where it is now.

[Roy from Pa]

 

[Mad Max]

Looks good
On the side sanding you have to take a good bit off to make it line up.
Nice work

[kenboonejr]

Thanks guys!  I really appreciate all the help.

[IanBB]

Not deeper but lower. If you have twist you can lower the nock on the weak limb to bring it back in line. I had a heavy recurve that didn't want to line up and was able to bring it back nicely into line but having the grooves on different levels, done well it doesn't even notice. It's not ideal but it can work.

[Mad Max]

Make sure you post pictures when your done

[kenboonejr]

Make sure you post pictures when your done

Will do Mad Max.  I'm sure I'll have a few more questions before I am done though

[Mad Max]

 

[Crooked Stic]

Here is the thing. To avoid needing to adjust twist out be sure your form is right be sure your lam grind is almost perfect especially side to and your limb layout is good and most times center will be center provided your grooves are same depth. I always start with tips wider than finished width. And get the limb pulling straight by deepening the groove on the weak side. I have never had much luck sanding the strong side.

[Shredd]

  Good to see everything worked out... Wanna see pics when done...

Now go get a haircut...   Just kidding...  Had long hair for years...

[kenboonejr]

  Good to see everything worked out... Wanna see pics when done...

Now go get a haircut...   Just kidding...  Had long hair for years...

That's funny.   That is exactly what my 101 year old grandmother told me the last time she saw me too! 
BTW.. I had short hair for years