Hi Loc fasteners

[monty2008]

My question is all I have in my current stock are tension type Hi Locs. I would like to install in place of shear type Hi Locs but install the shear type collar HL79 to maintain it's shear type character. Has anyone seen any type reference that allows me to do this? I was told along time ago by a boeing rep that this would be allowable but I can't find any mention of this in any SRM chapter 53-30-2. could someone provide a ref document.

 

[SWComposites]

Protruding tension or flush head tension fasteners?

Install them where in what?

 

[monty2008]

they are protruding head tension fasteners. We are working on a B727-200A frame repairs

 

[bf109g]

Have you looked at 727 SRM 51-30-3 for fastener substitution?

 

[rb1957]

i would have little problem replacing shear Hi-Loks with tension Hi-Loks ... the shear allowables are the same

 

[SWComposites]

Yes, in this application, there should be no problem with replacing the protruding shear head HiLoks with protruding tension head HiLoks. Where you find a specific document approving this for a 727 is a different problem; are you referring to the 727 SRM? did you check section 51? have you tried contacting Boeing customer service?

 

[rb1957]

whilst i'd've thought it was a pretty standard substitution, it may have not made it's way into a 727 SRM.

i wouldn't ask boeing for the approval, i'd approve it myself (with a 337?)

 

[bf109g]

I'd go with the internal approval, too. You can show equivalent shear strength. Just be sure that you don't have a radius interference issue with the larger heads.

 

[monty2008]

A special thanks to all who have replied. I have found the information that I was looking for.