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worn bolts

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frank.goodnight(at)att.ne
Guest

Posted: Wed Apr 15, 2009 11:33 am Post subject: worn bolts

My firestar2 has only got 75 hrs. on it. Today I took the bolts out of  

the universal joint at the

rear of the wings. I was shocked to find that one of them had a ring  

about 1/32 of an inch

deep worn around it. I don"t know why only one bolt was worn and the  

others were ok.

Maybe it was a little to loose, they have to be loose enough for the  

universal to work.

At any rate with another 75 hrs. ti would have worn enough to be  

really spooky.

Anyone else have this problem? I will remove and check ALL airframe  

bolts at my 100 hr. check.

Frank Goodnight

Brownsville, TX.

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Wed Apr 15, 2009 11:50 am Post subject: worn bolts

I was shocked to find that one of them had a ring

 	  Quote: 	
		   about 1/32 of an inch

 deep worn around it.


	


 	  Quote: 	
		   Frank Goodnight


	


Probably the cad plating was worn off.  I'd have to go do some research to 

find out how thick the cad plating is on aircraft bolts.  Its on there to 

lubricate and protect the bolt, self sacrificial.



I don't fold, so all my bolts are snugged up tight.  If I did have to fold 

each time I flew, I think I might snug up the bolts prior to flight, then 

loosen them up a bit to fold.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

frank.goodnight(at)att.ne
Guest

Posted: Wed Apr 15, 2009 12:12 pm Post subject: worn bolts

Hi John,

The wear is much deeper than the plating.I do fold every time I  

fly,It's a lot of trouble

but fits my budget better than hanger rent. It's also rough on my  

airplane.

Frank Goodnight

Firestar2

HKS

On Apr 15, 2009, at 2:49 PM, John Hauck wrote:

 	  Quote: 	

 >

 I was shocked to find that one of them had a ring

> about 1/32 of an inch

> deep worn around it.

> Frank Goodnight

 Probably the cad plating was worn off.  I'd have to go do some  

 research to find out how thick the cad plating is on aircraft  

 bolts.  Its on there to lubricate and protect the bolt, self  

 sacrificial.

 I don't fold, so all my bolts are snugged up tight.  If I did have  

 to fold each time I flew, I think I might snug up the bolts prior to  

 flight, then loosen them up a bit to fold.

 john h

 mkIII

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Wed Apr 15, 2009 12:17 pm Post subject: Re: worn bolts

Its a real good idea to check all bolts and fittings that could wear with vibration.   I put Mobil 1 Synthetic grease on all bolts and fittings that move against each other.  This grease is hard to find, but its worth the effort, its far better than any other grease I have ever used.   Some will say that grease will attract and hold dirt, which is true.  While not perfect, my greased joints have not worn all in just over 200 hours.  A greased fitting, even though not perfectly clean is far better than metal vibrating against metal.  Where others have been getting wear, I do not get any.



There is the added benefit of zero corrosion in these areas also.



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

russ(at)rkiphoto.com
Guest

Posted: Wed Apr 15, 2009 12:39 pm Post subject: worn bolts

Jetpilot

Aren't you in  the Miami area?

And you have "zero corrosion"  that close to salt water? And very  

salty water at that. I find  that hard to believe.

Russ K

do not archive



On Apr 15, 2009, at 4:17 PM, JetPilot wrote:



 	  Quote: 	
		   



 Its a real good idea to check all bolts and fittings that could  

 wear with vibration.   I put Mobil 1 Synthetic grease on all bolts  

 and fittings that move against each other.  This grease is hard to  

 find, but its worth the effort, its far better than any other  

 grease I have ever used.   Some will say that grease will attract  

 and hold dirt, which is true.  While not perfect, my greased joints  

 have not worn all in just over 200 hours.  A greased fitting, even  

 though not perfectly clean is far better than metal vibrating  

 against metal.  Where others have been getting wear, I do not get any.



 There is the added benefit of zero corrosion in these areas also.



 Mike



 --------

 &quot;NO FEAR&quot; -  If you have no fear you did not go as fast  

 as you could have !!!



 Kolb MK-III Xtra, 912-S





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 39346#239346

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Wed Apr 15, 2009 1:46 pm Post subject: Re: worn bolts

 	  russ(at)rkiphoto.com wrote: 	
		  Jetpilot

Aren't you in  the Miami area?

And you have "zero corrosion"  that close to salt water? And very  

salty water at that. I find  that hard to believe.

Russ K

do not archive



	




Yes, zero corrosion in my greased joints.  I don't know why that seems hard to believe, grease is an excellent, think corrosion preventative that is thick and does not evaporate over time like many of the light oils do.  If you have doubts as to if it works or not, try it on one elevator half pivot bolt, or other high wear area, and leave the other side dry, and compare your results after the next 100 hours.



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

russ(at)rkiphoto.com
Guest

Posted: Wed Apr 15, 2009 2:10 pm Post subject: worn bolts

Sorry, jetpilot, my mistake.

When you said you had  "zero corrosion"  I assumed you meant no  

corrosion anywhere. Obviously there'll be  no corrosion under a film   

of grease.

I still recall the endless polishing  by the guys who had polished- 

aluminum Cessnas -- even many miles from  the coast.

Russ K

do not archive



On Apr 15, 2009, at 5:46 PM, JetPilot wrote:



 	  Quote: 	
		   

 russ(at)rkiphoto.com wrote:

> Jetpilot

> Aren't you in  the Miami area?

> And you have "zero corrosion"  that close to salt water? And very

> salty water at that. I find  that hard to believe.

> Russ K

> do not archive

 Yes, zero corrosion in my greased joints.  I don't know why that  

 seems hard to believe, grease is an excellent, think corrosion  

 preventative that is thick and does not evaporate over time like  

 many of the light oils do.  If you have doubts as to if it works or  

 not, try it on one elevator half pivot bolt, or other high wear  

 area, and leave the other side dry, and compare your results after  

 the next 100 hours.



 Mike



 --------

 &quot;NO FEAR&quot; -  If you have no fear you did not go as fast  

 as you could have !!!



 Kolb MK-III Xtra, 912-S





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 39365#239365

lucien

Joined: 03 Jun 2007
Posts: 721
Location: santa fe, NM

Posted: Wed Apr 15, 2009 2:18 pm Post subject: Re: worn bolts

 	  frank.goodnight(at)att.ne wrote: 	
		  My firestar2 has only got 75 hrs. on it. Today I took the bolts out of  

the universal joint at the

rear of the wings. I was shocked to find that one of them had a ring  

about 1/32 of an inch

deep worn around it. I don"t know why only one bolt was worn and the  

others were ok.

Maybe it was a little to loose, they have to be loose enough for the  

universal to work.

At any rate with another 75 hrs. ti would have worn enough to be  

really spooky.

Anyone else have this problem? I will remove and check ALL airframe  

bolts at my 100 hr. check.

Frank Goodnight

Brownsville, TX. 	




I never actually pulled the bolts on mine (I hope Bob does at some point), but I did at one point pull the joint apart to troubleshoot the little bit of slop at the channel bracket where it bolts to the frame. 



That whole joint is well designed (IMO), but is fairly low tech. It doesn't have to be high-tech because it's not a high speed or constantly moving joint, but it can eventually start to wear if you fold the wings a lot. 



If the bolts are that worn I'd also check for slop at that channel bracket, as if it gets too bad it can change the AoA of the wing panel slightly. The original builder of my plane used shims of some kind under the channel bracket to tighten it up (he folded it all the time too).



I'd treat the bolts and the channel brackets as consumables if I folded every flight (i.e. I'd have spares on hand and would replace on a regular basis)....



LS

_________________
LS
Titan II SS

jbhart(at)onlyinternet.ne
Guest

Posted: Wed Apr 15, 2009 2:24 pm Post subject: worn bolts

At 02:31 PM 4/15/09 -0500, you wrote:

 	  Quote: 	
		  



Anyone else have this problem? I will remove and check ALL airframe  

bolts at my 100 hr. check.




	


Frank,



Steel on steel is not good.  I have had a similar problem with my FireFly.  

I solved it by bushing the holes.  See:



http://www.thirdshift.com/jack/firefly/firefly128.html



Fly safe,



Jack B. Hart FF004

Winchester, IN

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Wed Apr 15, 2009 2:28 pm Post subject: worn bolts

At 03:49 PM 4/15/2009, John Hauck wrote:

 	  Quote: 	
		  



Probably the cad plating was worn off.  I'd have to go do some research to 

find out how thick the cad plating is on aircraft bolts.  Its on there to 

lubricate and protect the bolt, self sacrificial.


	


Cad plating is at most .0005" thick, according to the MIL-Spec... Frank 

said his bolts are worn 1/32" (.03125"), which is sixty times more than the 

plating thickness.



-Dana

--

  A cement mixer collided with a prison van on the highway. Motorists are 

asked to be on the lookout for sixteen hardened criminals.

Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Wed Apr 15, 2009 2:33 pm Post subject: worn bolts

At 06:18 PM 4/15/2009, lucien wrote:



 	  Quote: 	
		  That whole joint is well designed (IMO), but is fairly low tech. It 

doesn't have to be high-tech because it's not a high speed or constantly 

moving joint, but it can eventually start to wear if you fold the wings a lot.


	


The amount of wear from folding (1/4 revolution each fold) is probably 

insignificant compared to wear from vibration and changing flight loads, 

unless something is way too tight or binding badly.



OTOH, the looseness required for folding allows more motion (and thus wear) 

than tight bolts.



-Dana

--

  A cement mixer collided with a prison van on the highway. Motorists are 

asked to be on the lookout for sixteen hardened criminals.

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Wed Apr 15, 2009 3:36 pm Post subject: Re: worn bolts

 	  russ(at)rkiphoto.com wrote: 	
		  Sorry, jetpilot, my mistake.

When you said you had  "zero corrosion"  I assumed you meant no  

corrosion anywhere. 	




Yes, even with powder coating, the rest of the airplane requires some  attention.  There are some areas where I have had to remove the powder coating where it gets chipped, or for whatever reason has not sealed well, and sand off the corrosion and use Epoxy Primer.   Corrosion X helps with the inside of the boom tube, and I will be putting Corrosion X it in the wing spars for the first time soon.  



Fortunately, I am in an enclosed hanger which helps a lot.  A Kolb left outside here would not last long      



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

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