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warp drive extension again - bolts this time

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lucien

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

Posted: Mon Mar 02, 2009 7:49 pm Post subject: warp drive extension again - bolts this time

Hi all,



I posted this over on the titan list, but I know some of you guys run the warp drive prop with Warp's 3" extension, so Im cuttin-and-pastin my query here as well. 



I've bitten the bullet and am replacing my IVO with a warp drive and 3" extension. My 912's prop flange has the lugs pressed into the holes in the outermost ring. These holes are threaded with 8mm x 1.25 pitch threads.



My question to ya'll is, what size and grade of bolts do you use to attach the extension to the flange? i.e. length below the head, length of shank, length of threaded portion? As for grade, I think the main options for metric are 8.8, 10.9 and 12.9 (and stainless steel).



I talked to Daryl today about this on the phone, he told me they needed to be about 1 1/2" long and grade 8. The grading system is different for 8mm bolts tho. 



It looks like M8 x 40 bolts fit what Daryl was describing. He said he didn't have any, so I'm trying scare up a set of correct bolts when the prop comes in next week. I have found socket-head bolts that seem to be exactly right according to his description, but I'm not sure of the grade I should get.



I might call him again tomorrow to ask if what I have will work, but don't want to pester him unecessarily if I don't have to .



Thanks,



LS

_________________
LS
Titan II SS

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Mon Mar 02, 2009 8:39 pm Post subject: warp drive extension again - bolts this time

[quote] ---

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JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Mon Mar 02, 2009 8:42 pm Post subject: Re: warp drive extension again - bolts this time

Kolb might have some of those on hand, I would call Travis and ask him.  If he does not have stuff like this in stock, he usually knows exactly where to find it     



Mike

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

Kolb MK-III Xtra, 912-S

Dana

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

Posted: Tue Mar 03, 2009 4:10 am Post subject: warp drive extension again - bolts this time

At 10:49 PM 3/2/2009, lucien wrote:



 	  Quote: 	
		  My question to ya'll is, what size and grade of bolts do you use to attach 

the extension to the flange? i.e. length below the head, length of shank, 

length of threaded portion? As for grade, I think the main options for 

metric are 8.8, 10.9 and 12.9 (and stainless steel).

I talked to Daryl today about this on the phone, he told me they needed to 

be about 1 1/2" long and grade 8...


	


Without getting into what grade to hold your prop on (because I don't know):



AN bolts (which have been used to hold on props for years) aren't graded 

per se, but are roughly equivalent to U.S. Grade 5, which is equivalent to 

metric grade 8.8.  Grade 8 is equivalent to metric 10.9.  There is no 

direct U.S. equivalent for 12.9, which is a very high strength bolt that I 

would think would too brittle for a prop application.



-Dana



--

  Suicidal twin kills sister by mistake!

jlsk1(at)frontiernet.net
Guest

Posted: Tue Mar 03, 2009 5:03 am Post subject: warp drive extension again - bolts this time

At the recomendation of the guy that makes the Sabre prop extensions, (per 

Travis'  instructions)Get the measurements you want, the call Mayland 

metrics & order either grade 8 or grade 5 from them. Thats what I just did & 

they are great to work with & order from. They will take your U.S. 

measurements & convert them  to metric & ship them right out.

http://mdmetric.com/indexg.html?gclid=CPajwc7V9ZcCFQazsgodwk2RDA



Jim Kmet

Cookeville , TN

MK-3C soon to start the 912

Warp & Sabre combo

(All my measurements are at the airport, & won`t be out there fore a few 

more days when it finally warms up)

---

jlsk1(at)frontiernet.net
Guest

Posted: Tue Mar 03, 2009 6:17 am Post subject: warp drive extension again - bolts this time

Sorry, thats MARYLAND metrics

Jim

do not archive

---

aslsa.rng(at)gmail.com
Guest

Posted: Tue Mar 03, 2009 6:21 am Post subject: warp drive extension again - bolts this time

Dana, et al, We've had this discussion before, but to be brief, AN bolts conform to the spec for Grade 6, not Grade 5. The difference is that Grade 5 are carbon steel like Grade 8, while AN bolts are alloy steel, roughly equivalent to 4130.  The difference of importance is that an AN bolt actually gets stronger when bent, while Grade 5 and 8, especially Grade 8, are brittle and break.

You are right that metric 8.8 is equivalent to an AN, and 10.9 is equivalent to Grade 8 as such 8.8 is the proper selection for prop bolts.

 Lucien, Daryl builds good props, but his advice to use Grade 8's is inconsistent with the rest of the world. Power Fin, for instance, ships their props with SS socket head cap screws (SHCS) which are roughly 60% as strong as the AN and metric 8.8's bolts of the same size, but allows the use of metric 8.8 bolts, too. 

 The issue is ductility, not strength. The SS shcs, 8.8's and AN bolts will absorb the vibration and torque pulses of the engine. The Grade 8's will work harden and fracture.

Rick

 do not archive



On Tue, Mar 3, 2009 at 6:07 AM, Dana Hague <d-m-hague(at)comcast.net (d-m-hague(at)comcast.net)> wrote:

[quote] --> Kolb-List message posted by: Dana Hague <d-m-hague(at)comcast.net (d-m-hague(at)comcast.net)>

 

 At 10:49 PM 3/2/2009, lucien wrote:

 

 

 	  Quote: 	
		   My question to ya'll is, what size and grade of bolts do you use to attach the extension to the flange? i.e. length below the head, length of shank, length of threaded portion? As for grade, I think the main options for metric are 8.8, 10.9 and 12.9 (and stainless steel).

 

 I talked to Daryl today about this on the phone, he told me they needed to be about 1 1/2" long and grade 8...

 	
 

 Without getting into what grade to hold your prop on (because I don't know):

 

 AN bolts (which have been used to hold on props for years) aren't graded per se, but are roughly equivalent to U.S. Grade 5, which is equivalent to metric grade 8.8.  Grade 8 is equivalent to metric 10.9.  There is no direct U.S. equivalent for 12.9, which is a very high strength bolt that I would think would too brittle for a prop application.

  

 -Dana

 

 --

  Suicidal twin kills sister by mistake!



 

 

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[b]

lucien

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

Posted: Tue Mar 03, 2009 7:07 am Post subject: Re: warp drive extension again - bolts this time

 	  aslsa.rng(at)gmail.com wrote: 	
		  Dana, et al, We've had this discussion before, but to be brief, AN bolts conform to the spec for Grade 6, not Grade 5. The difference is that Grade 5 are carbon steel like Grade 8, while AN bolts are alloy steel, roughly equivalent to 4130.ï¿½ The difference of importance is that an AN bolt actually gets stronger when bent, while Grade 5 and 8, especially Grade 8, are brittle and break.

You are right that metric 8.8 is equivalent to an AN, and 10.9 isï¿½equivalent to Grade 8 as such 8.8 is the proper selection for prop bolts.

 Lucien, Daryl builds good props, but his advice to use Grade 8's is inconsistent with the rest of the world. Power Fin, for instance, ships their props with SS socket head cap screws (SHCS) which are roughly 60% as strong as the AN and metric 8.8's bolts of the same size, but allows the use of metric 8.8 bolts, too.ï¿½

 The issue is ductility, not strength. The SS shcs, 8.8's and AN bolts will absorb the vibration and torque pulses of the engine. The Grade 8's will work harden and fracture.

Rick

 do not archive

	




Speaking of that, I happened to rob the hub bolts out of my powerfin that I still have last night and noticed they're the exact size (M8 x 40) that it looks like Daryl recommended . 



And yes they are stainless steel SHCS's (I ran powerfins for a long time on my 2-strokes). 



So it sounds like SS is preferred over the other options that seem to be available for metric hardware (i.e. class 8.8 through 12.9)?



it strikes me as very bizarre that we have to go the hardware store for metric bolts and there doesn't seem to be an aircraft grade set for metric. I've been all over the internet last day or so and can't find anything analogous to AN/MS/NAS etc for metric bolts.



What do you guys with extensions have holding yours on at the moment? I'll go get that if it's different than the SS's I have.



I may call Daryl again today and see if I can get a specific recommendation. It'd be nice to have them when the prop comes in next week...



LS

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LS
Titan II SS

John Hauck

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

Posted: Tue Mar 03, 2009 7:58 am Post subject: warp drive extension again - bolts this time

> What do you guys with extensions have holding yours on at the moment? 

I'll go get that if it's different than the SS's I have.

 	  Quote: 	
		  

 I may call Daryl again today and see if I can get a specific 

 recommendation. It'd be nice to have them when the prop comes in next 

 week...



 LS


	




Lucien:



I use Daryl's props and Daryl's recommendation for fasteners, 8.8.



I do not use SS.  They might be alright, but SS is not as stress resistant.



I buy my bolts locally, drill the heads for safety wire myself.



Have had good luck with them, more than 2,600 hours without a failure.



Friction between the prop, extention (I use a 4"), and the prop flange, is 

carrying the torsional loads.  The prop flange as well as the extention are 

equipped with drive lugs.  I don't think the prop bolts are getting a 

beating on my airplane.



john h

mkIII

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

lucien

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

Posted: Tue Mar 03, 2009 8:53 am Post subject: Re: warp drive extension again - bolts this time

 	  John Hauck wrote: 	
		  

Lucien:



I use Daryl's props and Daryl's recommendation for fasteners, 8.8.



I do not use SS.  They might be alright, but SS is not as stress resistant.



I buy my bolts locally, drill the heads for safety wire myself.



Have had good luck with them, more than 2,600 hours without a failure.



Friction between the prop, extention (I use a 4"), and the prop flange, is 

carrying the torsional loads.  The prop flange as well as the extention are 

equipped with drive lugs.  I don't think the prop bolts are getting a 

beating on my airplane.



john h

mkIII 	




Ah, how much you want to bet that was along the lines of what Daryl said and the disconnect is between the phone and the chair...... 



Do you use fully threaded bolts or ones with a shoulder on them? I couldn't find the 8.8 grade locally that actually had a shoulder, they were all fully threaded........



2600 hours is good enough for me, I'll tell you what .



Thanks all for helping a current Kolb infidel (tho the firefly idea is still drilling around in my mind)...



LS

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LS
Titan II SS

John Hauck

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

Posted: Tue Mar 03, 2009 9:11 am Post subject: warp drive extension again - bolts this time

> Do you use fully threaded bolts or ones with a shoulder on them? I 

couldn't find the 8.8 grade locally that actually had a shoulder, they were 

all fully threaded........

 >

 	  Quote: 	
		   LS


	




Lucien:



Wouldn't use a fully threaded bolt for a prop bolt.



Santa Fe should have a fastener shop.  I get my bolts at a local shop like 

Fastenal, or something like that.



I did have to drill the heads of the bolts for safety wire.  Could not get 

drilled metric prop bolts.



john h

mkIII

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

Dana

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

Posted: Tue Mar 03, 2009 10:19 am Post subject: warp drive extension again - bolts this time

At 09:20 AM 3/3/2009, Richard Girard wrote:

 	  Quote: 	
		  Dana, et al, We've had this discussion before, but to be brief, AN bolts 

conform to the spec for Grade 6, not Grade 5. The difference is that Grade 

5 are carbon steel like Grade 8, while AN bolts are alloy steel, roughly 

equivalent to 4130.


	


I said "roughly equivalent", not "interchangeable with... an AN bolt is 

~125ksi whereas a Grade 5 is 120ksi.  There is no Grade 6 (well, doubtless 

there is but you won't find Grade 6 bolts for sale anywhere)  The actual 

tensile strength of a Grade 5 bolt will generally be lower, too, as Grade 

5's are most commonly coarse thread, with a smaller root diameter than the 

fine thread AN's.



Actually Grade 8 (but not Grade 5) is indeed alloy steel.



-Dana

--

  Grow your own dope! Plant a politician!

lucien

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

Posted: Tue Mar 03, 2009 12:44 pm Post subject: Re: warp drive extension again - bolts this time

 	  John Hauck wrote: 	
		  

Lucien:



Wouldn't use a fully threaded bolt for a prop bolt.



Santa Fe should have a fastener shop.  I get my bolts at a local shop like 

Fastenal, or something like that.



I did have to drill the heads of the bolts for safety wire.  Could not get 

drilled metric prop bolts.



john h

mkIII 	




Well I'll be darned.... sure enough, we have a Fastenal here in town.... 



Went by and got some 8.8 bolts, went over it on the phone with Daryl after getting to the hangar and it looks like these are about right (M8 x40 partial thread). 



Course I'll know for sure once the prop gets here, which should be early next week...



Thanks for all the help guys,



LS

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Titan II SS

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