Hi-Lite interference fit installation tools. 2

[sferrin]

New here. Is anybody aware of any available tooling for forcing a Hi-Lite pin into an interference fit hole in a ti/al stack? Some kind of hand-held pneumatic or hydraulic puller maybe? It's on the structure and no "around the edge" access and nothing to clamp to on the entry side. Typically I've seen close tolerance holes used but not interference fit. It looks like there are some here who've encountered this situation so I thought I'd ask how they dealt with them.

Regards.

 

[rb1957]

Normal Hi-Lite installation tools ... should do the job.

maybe talk to FTI (Fatigue Technology Inc) ... re ForceMate interference fasteners.

another day in paradise, or is paradise one day closer ?

 

[WKTaylor]

Hi-Lok, Hi-Lite, Hi-Tigues, Etc are LISI product [was: Hi Shear]

https://www.lisi-aerospace.com/en/products/fasteners/

I'm pretty sure that Hi-Lite [HST] pins are a lightweight version of Hi-Lok [HL] pin... suitable only for light interference.

True interference in Al/Ti sandwich as You described is more suited for 'Hi-Tigue [HLT] pins.

LISI has good tech support... contact them to discuss installation practices.

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[edmeister]

As Will T. indicated - Hi-Lite/ Hi-Lok are designed for "light interference".
On thick stackups - ensure that the hole diameter is on the "larger side".
Is access available on the "head' side - use a alum/brass punch to hammer the fastener in.
In some blind locations use a MS21042-X nut with washer stackup to draw the fastener in - then replace with the correct collar.
- if all fails - verify the fastener & material diameters. Are you using reamers?

many techs / MROs use "custom" reamers skewed to the higher end of the diameter.​

- last thing you want is to have the pin "pinched" in a blind location with no access to punch it out.
- errata : when installing in Stainless sheets - Holes were always to be on the "higher" side of the diameter. Whereas Alum pins were installed on the "lower" side.
- What Fastener diameters are u dealing with? Typ -6, -8 or -12 & up. Large Diameters always require "looser" holes - especially in thick materials.
- on initial insert - are any threads showing?
I would not "force" a pin in beyond typical effort. Something is just wrong. This will just cause issue - either to the pin or the material.
Also consider the poor bloke who may have to remove the pin sometime later. It you installed via hydraulics .. what is he to do to remove?

 

[mfgenggear]

sferrin

I suggest as well as the great advice above to also take a walk on the floor and talk to the technicians assembling on the floor. if it is a new design build a test
assembly to refine the installation process. don't build thousands of parts a find there is an issue. it's been a long time since I was involved with assemblies and installations. but most fasteners had specialty designed and built tools for the special fasteners. don't remember any issues unless there issues with access. EG: clearance, requires blind fasteners. in order for the holes to line up match drill and ream was required. a whole book can be written about the million different scenarios.

 

[WKTaylor]

A couple of added points...

NAS618 FASTENER, RECOMMENDED SHANK, HOLE AND HEAD-TO-SHANK FILLET RADIUS LIMITS
This spec defines various limits for fastener shank-to-hole fits. On my jet we are limited to 'transition fit' [net-fit, etc]… due to older alloys that are SCC prone.

Ensure that the alloys You are fastening with interference fit have MINIMUM stress corrosion cracking [SCC] threshold of KIscc = 25-KSI ALL MATERIAL ORIENTATIONS [ST, LT, L] to ensure SCC will NOT be an issue.

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]