Have I cut my rod end too short?

[glowa]

Needed to cut my rod end for fox shock clearance, one side is flush with the nut as visible in the pic, the other side is maybe 2 threads sticking out. Someone told me that flush is too short and that this could break, does not make sense to me but I would rather ask here

 

[ak]

As long as the nylock is contacting the threads it should be fine.

 

[mountainhorse]

Liberal use of blue locktite after cleaning with brake cleaner and drying for good measure IMO.


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[glowa]

nylock is contacting but I will put loctite regardless!

 

[LoudHandle]

Three full threads is considered the minimum engagement by engineering strength calculations, to avoid pull out / stripping at the recommended torque. That is why jam nuts and aircraft jet nuts are essentially 1/2 the fastener diameter thick, to get the three full threads plus a safety factor of one or two full threads.

The Maximum engagement that will do any good, is the diameter of the fastener. Which is why all standard nuts are roughly 1 diameter thick.

Anywhere in the middle is acceptable, if there is any doubt about the fastener loosening off, a minimum of blue Loc-tite or the equivilent is a good practice.

While it does not apply here; some structural codes require 3 threads visible above the nut, but that is more to identify and correct the fastener loosening off and provide a degree of safety margin before loosing the fastener completely. This is quite common on communication towers and bridges that may be subjected to conditions at the materials natural harmonic frequency. I have heard stories of the antenna on the Empire State Building not having any tightened fasteners left holding the base to the building during a wind storm and the tech's struggle to re-tighten them as it rocked back and forth in the gusts. Good story, but extremely un-nerving for him at the time of the ordeal. Had the fasteners not been required to be extra long the tower would have ended up in the streets below killing many unsuspecting victims. They now require all wind loaded structures to be double nutted as a minimum, in addition to the three thread rule.

FWIW

On a side note: If clearance is still an issue, I would forgo the inner nut entirely and install a Heli-coil in the Aluminum upper arms and use the jam nut on just the outboard end. Permanent Loc-tite the Heli-ciol to the arm and blu Loc-tite the rod end to the Heli-coil and Jam Nut. Again FWIW

 

[mountainhorse]

LH... Isn't that three threads past the steel and not three threads past the soft nylon??

Good tip on the heli coil... or timesert... I'm more of a fan of timeserts.


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[LoudHandle]

LH... Isn't that three threads past the steel and not three threads past the soft nylon??

Good tip on the heli coil... or timesert.


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The three thread full rule to avoid pull out is Three threads of the fastener mating to three threads of the nut (in this case the steel portion). But regardless of the actual fasteners material Three full threads engaged. If you choose to look at it differently three full turns on the nut before it comes tight is the absolute minimum.

The three threads past the actual fastener material is purely a bonus, regardless of whether they are in the nylon portion of the nut or not.

I hope that is clearer.

 

[glowa]

clearance is not an issue with the bolt being flush with the nut, clearance also should not be an issue with 3 threads sticking out.

Recommendations are recommendations but should I really replace this rod if its flush with the nut? LH!

 

[LoudHandle]

clearance is not an issue with the bolt being flush with the nut, clearance also should not be an issue with 3 threads sticking out.

Recommendations are recommendations but should I really replace this rod if its flush with the nut? LH!

IMO, you are fine, as pictured. I would have no reservations, running with it flush with the jam nut.

 

[glowa]

thank you LH