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  #1  
Old 08-24-2021, 07:24 PM
md9680 md9680 is offline
 
Join Date: Oct 2006
Location: Edgewood, NM
Posts: 139
Default Best way to remove bow from part

For some reason, one set of E-903 Outboard and E-904 Inboard Tip ribs were already fluted by someone when it was time to work with them. They appeared serviceable and, yes, one set went together well. However, the E-904 for the second set has a bow in the web which prevents it from making full contact with its E-904 counterpart, leaving a sizable gap at the edges when clecoed.

What's the best way to remove that bow?

Thanks.
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  #2  
Old 08-24-2021, 07:42 PM
Taltruda Taltruda is offline
 
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You can unflute two ways.. use the flat seamers and just squeeze lightly, don’t flatten it all the way out, or you can also carefully use the fluting plyers backwards and just take out a little of the hump without making it go the wrong way
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  #3  
Old 08-24-2021, 11:33 PM
md9680 md9680 is offline
 
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Quote:
Originally Posted by Taltruda View Post
You can unflute two ways.. use the flat seamers and just squeeze lightly, don’t flatten it all the way out, or you can also carefully use the fluting plyers backwards and just take out a little of the hump without making it go the wrong way
Thanks, Taltruda, but it currently sits perfectly flat on a truly flat surface, so "unfluting" doesn't appear to be required.

But the top web portions of both the E-903 and E-904 ribs have to be flat enough to be riveted to each other (see page 09-02, Figure 4). This can't happen because the E-904 rib has a longitudinal upward bow that prevents it from laying on the E-903 without rocking around like a cooking pan that rocks on the kitchen counter because it took a 30-year beating from someone with a potato masher.

I need to flatten the web of the rib inward without causing damage. The radius of the flange-to-web bend appears to have been significantly decreased in the process of bending the flanges to establish the required 90-degree angle, resulting in the outward/upward bowing of the rib's web. Maybe use some scrap lumber and a mallet to reshape the web?

There. Might have answered my own question. I'll deal with it tomorrow.

Thanks, again, for your thoughts.
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  #4  
Old 08-25-2021, 05:51 AM
mturnerb mturnerb is offline
 
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Forming ribs usually causes bowing in such a way that fluting between rivet holes on the flanges should flatten the web. I ended up fluting the E-904 ribs to fit. IIRC E-903's came fluted but I adjusted a little for perfect fit.

Example:

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Last edited by mturnerb : 08-25-2021 at 07:09 AM.
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  #5  
Old 08-25-2021, 07:05 AM
Taltruda Taltruda is offline
 
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Oh I think I understand what you need now.. ok how about using a bean bag or perhaps a thin carpet at support and a 1x1 piece of wood and a hammer to gently pop out the warping? Remember this isn’t rocket surgery here..
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  #6  
Old 08-25-2021, 07:25 AM
mturnerb mturnerb is offline
 
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Quote:
Originally Posted by Taltruda View Post
Oh I think I understand what you need now.. ok how about using a bean bag or perhaps a thin carpet at support and a 1x1 piece of wood and a hammer to gently pop out the warping? Remember this isn’t rocket surgery here..
If only the web is bowed this makes sense. I wonder if flattening the web would cause reactive bowing of flanges.
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  #7  
Old 08-25-2021, 07:35 AM
NavyS3BNFO NavyS3BNFO is offline
 
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Location: Northern NJ
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If I understand your issue correctly, you could use a couple C-clamps to clamp the webs together tightly and then rivet them. Once you have a couple rivets in, you can probably remove the clamps or readjust them as you go to keep the webs squeezed tightly together.

I've found that spring clecos sometimes don't have enough clamping force. There are also cleco clamps and draw type wingnut clecos that provide more clamping force.
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  #8  
Old 08-25-2021, 08:21 AM
md9680 md9680 is offline
 
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Quote:
Originally Posted by mturnerb View Post
...I wonder if flattening the web would cause reactive bowing of flanges.
I figure it will but I have the tools to fix that.
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  #9  
Old 08-25-2021, 08:28 AM
md9680 md9680 is offline
 
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Quote:
Originally Posted by NavyS3BNFO View Post
...C-clamps to clamp the webs together tightly and then rivet them...spring clecos sometimes don't have enough clamping force...
I like your idea of the C-clamps. I guess it didn't occur to me because, at the time, I was counting on the clecos pulling everything together but, as you say, they don't have enough force. Thanks.
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  #10  
Old 08-26-2021, 09:15 AM
md9680 md9680 is offline
 
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Well, guys, I managed to use the E-913 Counterbalance Skin to basically "force" the bow out. It took some doing to cleco, but it's now ready for future riveting.
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