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Hole Flanging
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ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Fri Feb 15, 2008 7:13 am Post subject: Re: Hole Flanging

As long as it works. I figured it was probably the die pinching something too much.



do not archive



 	  Ron Lendon wrote: 	
		  Andy,



The crowning I got in the rear ribs was all my fault for making the die clearance to small (I made em to close) and coining the parts in a press.  It really was faster to just add the L-angles rather than all the hand work.  The parts were flat before the flanging operation, and they are also flat now in the completed wing.

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psm(at)ATT.NET
Guest

Posted: Fri Feb 15, 2008 9:06 am Post subject: Hole Flanging

Hi guys,



The bowing of the ribs when using flanging dies is a characteristic 

of metal bending rather than a fault with the dies.  It is called 

"Spring Back" and happens whenever metal is bent.



The spring back makes the web bow because it happens all the way 

around the bent circle.  It can easily be removed with a slotted 

stick by bending the flange a little bit further than its final 

position after going through the flanging die.  You don't need to add 

"L" reinforcements to straighten the rib webs.



A similar phenomenon happens when bending the flanges around the edge 

of the ribs that makes them bow the rib web and have a less than 90 

degree angle to the web.  This can be fixed with the fore-mentioned 

slotted stick or a small "Seaming" tool - a set of pliers with 

somewhat fatter jaws.  You can also use the pronged fluting tool 

provided with Zenith kits for this purpose.



I don't know what the impact of adding "L"s to the ribs might be.  It 

probably is OK so long as you don't mind the small weight addition.



Have fun,



Paul

XL fuselage

At 07:08 PM 2/12/2008, you wrote:

 	  Quote: 	
		  William, I used the flanging dies made of wood and I experienced the 

same problem as you did.

The rib webs were bowed.

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ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Fri Feb 15, 2008 9:18 am Post subject: Re: Hole Flanging

I really haven't seen any bowing on my ribs. Theoretically, the flange part of the hole should get stretched slightly and the skin should get thinner, more so as you move more towards the hole part of the flange. If the skin doesn't get stretched enough to accommodate the larger diamter the flange edge is being pressed into in the die as the flange is formed, the rest of the rib will need to bow to accommodate it's new form. Measuring my rib hole flanges, at the very edge of the flange the skin is only about .021 whereas it started out as .025.



Taking this to the extreme, if the flange was wider, the sheet would get thinner and thinner to stretch around that hole, actually, it would crack first. I've had that happen once and it was due to not deburring the hole good enough before it went in the flange die.



 	  psm(at)ATT.NET wrote: 	
		  Hi guys,



The bowing of the ribs when using flanging dies is a characteristic 

of metal bending rather than a fault with the dies.  It is called 

"Spring Back" and happens whenever metal is bent.



The spring back makes the web bow because it happens all the way 

around the bent circle.  It can easily be removed with a slotted 

stick by bending the flange a little bit further than its final 

position after going through the flanging die.  You don't need to add 

"L" reinforcements to straighten the rib webs.



A similar phenomenon happens when bending the flanges around the edge 

of the ribs that makes them bow the rib web and have a less than 90 

degree angle to the web.  This can be fixed with the fore-mentioned 

slotted stick or a small "Seaming" tool - a set of pliers with 

somewhat fatter jaws.  You can also use the pronged fluting tool 

provided with Zenith kits for this purpose.



I don't know what the impact of adding "L"s to the ribs might be.  It 

probably is OK so long as you don't mind the small weight addition.



Have fun,



Paul

XL fuselage

At 07:08 PM 2/12/2008, you wrote:

 	  Quote: 	
		  William, I used the flanging dies made of wood and I experienced the 

same problem as you did.

The rib webs were bowed.

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n4546v(at)mindspring.com
Guest

Posted: Fri Feb 15, 2008 9:55 am Post subject: Hole Flanging

do not archive



Sounds like a good, workmanlike system to flange holes in ribs & short

parts, but you didn't answer my question you yourself quoted below:  How

long does it take to stage things to do a hole in the center of a 12' wing

spar web?



Is your vise on a workbench?  What supports must you organize to support

wing spar material you are flanging 6' on each side of your vise?



Best Regards,



Randy, Las Vegas



Subject: Re: Hole Flanging

 	  Quote: 	
		   



 Takes me about 60 seconds. I put one half of the die in the vise, put the

rib in, put the other die on top, put the bolt through with the plate on one
	


side, put the plate on the other side, put the nut on, tighten the nut by

hand, then use a wrench the rest of the way.

 	  Quote: 	
		  

 Last time I timed it (because I had to remake one with the form already

finished), it took me about 80 minutes to make a wing center rib from flat
	


sheet to fully finished rib with flanged holes.

 	  Quote: 	
		  



 n4546v(at)mindspring.com wrote:

 > do not archive

 >

 > And, I didn't have to "juggle" any of the parts around. With your "nuts

&
	


 	  Quote: 	
		   > bolts & plates" how long does it take to get things positioned for each

 > press, especially one in the middle of a 12' wing spar web?

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ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Fri Feb 15, 2008 10:16 am Post subject: Re: Hole Flanging

Oh, spar hole. 5 minutes longer. I think I zipped my toolbox around one side and my table saw on the other side and then propped as needed.

Yes, my vise is on my workbench.

If I had to use the thing freehand for some reason, I don't see that being a problem either.

 	  n4546v(at)mindspring.com wrote: 	
		  do not archive

Sounds like a good, workmanlike system to flange holes in ribs & short

parts, but you didn't answer my question you yourself quoted below:  How

long does it take to stage things to do a hole in the center of a 12' wing

spar web?

Is your vise on a workbench?  What supports must you organize to support

wing spar material you are flanging 6' on each side of your vise?

Best Regards,

Randy, Las Vegas

Subject: Re: Hole Flanging

 	  Quote: 	

 Takes me about 60 seconds. I put one half of the die in the vise, put the

rib in, put the other die on top, put the bolt through with the plate on one

side, put the plate on the other side, put the nut on, tighten the nut by

hand, then use a wrench the rest of the way.

 	  Quote: 	

 Last time I timed it (because I had to remake one with the form already

finished), it took me about 80 minutes to make a wing center rib from flat

sheet to fully finished rib with flanged holes.

 	  Quote: 	

 n4546v(at)mindspring.com wrote:

 > do not archive

 >

 > And, I didn't have to "juggle" any of the parts around. With your "nuts

&

 	  Quote: 	
		   > bolts & plates" how long does it take to get things positioned for each

 > press, especially one in the middle of a 12' wing spar web?

- The Matronics Zenith-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Zenith-List

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