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Hi-Lok HL41 Joint Strength

Hi-Lok HL41 Joint Strength

Hi-Lok HL41 Joint Strength

Does anyone know of any joint shear and tensile strength data for HL41-4 A286 Flush Shear Head, in 2219-T62 or similar, out there in the public domain, or a believable calculation method?

RE: Hi-Lok HL41 Joint Strength

did you manage to get the spec sheet from lisi-aerospace ? (it took me some trouble, had to use chrome for the link to open). this is good if you think you're limited by the fastener shear strength, maybe check with your 2219 sheet ?

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

RE: Hi-Lok HL41 Joint Strength


I assume You do noT have any corporate standards for HL Pin/Collar Mechanical allowables?

Suggest calling Lisi-Hi-Shear folks direct. Their website lists Ph # for California location that was Hi-Shear HQ and is still a prime site for HL engineering and manufacturing.

See attached HL41 spec sheet that I downloaded awhile-back [when it was Hi-Shear and they had a really classy website].


I have a nice relationship with a LISI sales agent who sends me spec sheets within minutes of requesting them.

Also, I have known one of the tech support guys for +25-years who is an old gray hair like me with a vast corporate knowledge of Hi-lok pins and collars [and most other Hi-Shear vintage] parts, who can dig up stuff/info I never thought might exist. In fact, recently, he help me solve a puzzle with new HL P/N CRES-tension collars. But that's another story...

These folks may already have MIL-HDBK-5/MMPDS allowabes for the HL41 with one or more of the collars listed in the HL41 Pin spec sheet.


This CAUTION note is why getting exact allowables is not as easy as it seems... lots of possible collar combinations for each pin. You may have to accept "close-enough for government work" and get pin/collar allowables for parts similar to what You are requesting.

HL Shear pins MUST have a shear rated collar installed. Putting a tension rated collar on a shear rated pin is possible... but the excessive torque-tension at break-off may cause the head to crack/yield... or be overloaded in routine shear usage.

General ROTs...
A tension head HL pin can accept shear rated or tension rated collars... but the bold CAUTION NOTE applies!
A shear rated collar makes the fastener system shear rated [low tension].
A tension rated collar makes the fastener system shear-tension rated.
An aluminum collar generally has a 250F--300F service temp rating.
A 303 CRES collar may have a 450F--800F/900F service temp rating.

HL41 pin spec does NOT allow a cad plating or aluminum-organic coating option. It appears intended for use in a hot environment; and 'similar' type structural materials [CRES, Titanium, etc]. I would not use these pins in aluminum structure without a lot of isolation [fay surface and pin installation 'wet with sealant', etc].

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true.
o For those who believe, no proof is required; for those who cannot believe, no proof is possible.
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion"]
o Learn the rules like a pro, so you can break them like an artist. [Picasso]

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