Beaded Hi-Lites ??

[rb1957]

Ok, probably a question for Will ...

We've got "beaded Hi-lites" HSTB-409 to install. We're looking at one and they look just like a standard Hi-Lite ??

We're working on a GIV and these are in the wing skin (ie wet tank boundary) and actually need an oversize. Any ideas anyone ?
Please not "call Gulfstream".

 

[SWComposites]

fastener spec, https://jet-tek.com/hi-lite-pins/hstb409.pdf, says use HSTB109 for oversize.

wondering if "beaded" means a crowned head rather than flat.

 

[rb1957]

yes, that's the one source we found, but could not find any other reference for HSTB109.

fastener described as "beaded and crowned". AFAIK "crowned" means the head is slightly profiled (as "crowned") and this is flattened under installation to improve the CSK head interference. As for "beaded", we initially thought the fastener would have a proud bead on the shank, but it doesn't. It is possible it means the shank has been shot peened, but the surface finish doesn't match this idea either.

 

[MintJulep]

If you don't like "call Gulf Stream" as an answer, then how about "Call Hi-Shear".

The (presumably) current drawing HSTB-109 is rev. 4 - dated 1993. It doesn't contain the word "beaded".

If you're working on a G-IV then an earlier revision would have been in effect at the time the aircraft was designed.

 

[rb1957]

yeah, "beaded" is a word we picked up from the Jet-Tips site. We're a mod shop in Canada and don't have a relationship with Gulfstream. We could have our US operator call Gulfstream, but that'll lead to "20 questions" and I suspect a "no".

 

[WKTaylor]

Geezzz...

The HSTB409 is a 'shortened Hi-Tigue' ['Hi-Lite/Hi-Tigue'].

The Hi-Tigue equivalent to HSTB11 = HLT11.
The 1OS [+1/64] for HLT11 is HLT111... and the 2OS [+1/32] would be HLT211.


BTW... the bead is the 'shaded ring area at the end of the shank at the threads'... that is a barely perceptible polished/radiused-bulge which is supposed to run ahead of the shank in interference, 'smoothing' the hole wall for a tighter interference... without scoring/shaving the hole wall... unlike sharp-edge HLs will.

For Hi-Lok and Hi-Lite Nuts/Collars... https://www.lisi-aerospace.com/en/product/hi-lok-and-hi-lite-nuts-and-collars/
For Starlite Nuts... https://www.lisi-aerospace.com/en/product/starlite-nuts/

For LISI Pins... https://www.lisi-aerospace.com/en/products/fasteners/ ... then select...

 

[3DDave]

That sounds like a process to remove scratches while putting the wall of the hole in compression to reduce fatigue susceptibility.

 

[rb1957]

thx Will, and everyone.