Thread Locking Adhesive on leveling nuts?

[ReverenceEng]

We have an exterior base plate in a dry climate for a very light weight sign. Client doesn't normally use grout, and that's how most of these are done around here so they can easily swap out the sign as the tenant changes over the years (when axial load and bending on plate don't require the bearing area of the grout).

Anyway, so we have leveling nuts, and some architect or something that reviewed the plans asked the question about using a locking thread adhesive (like Loctite) for the leveling nuts, to which I kind of want to say "are you kidding me?"...never heard of using it in this application, or, at least never heard of the structural engineering specifying it.

If my client wants to use it, then fine, but I don't really see a need for me to specify...

Thoughts??

 

[SlideRuleEra]

...I kind of want to say "are you kidding me?"...never heard of using it in this application, or, at least never heard of the structural engineering specifying it.

The Caltrans report "Evaluation of Several Brands of Anaerobic Threadlocking Compounds Used for Various Bolting Applications" covers testing performed for the US Federal Highway Administration. Products are considered acceptable for certain structural uses.

Your client probably wants a "weaker" thread-locking blend so the nuts can be turned in the future.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[ReverenceEng]

That document is informative, but is there any requirement or guidance on the actual use of such a product for base plate leveling nuts? Likewise, should I specify, or just leave up to the installer...?

 

[dik]

If your client wants it, issue a revision to include for Locktite... I usually use Red... it's almost there forever... and you have to use a torch to loosen it... but, holds better than almost anything...

Dik

 

[MotorCity]

I Would advise against using a thread locking adhesive in your situation. By using it, you are defeating the purpose of leveling nuts.....to level or provide adjustment to the baseplate in the future. If the client does not want to use grout, I would use double nuts

 

[dik]

Depends on your soil type... often levelling nuts are used for the initial install, and then never adjusted.

Dik

 

[SlideRuleEra]

ReverenceEng - This seems like a really straight forward situation:

1. The leveling nuts are intended for reuse in the future.

2. The Client wants to use threadlocking compound on the leveling nuts, even though it may not be needed.

3. Thanks to Caltrans, you have now heard that (at least in principle) there are structural applications for threadlocking compounds.

4. Should you "just leave up to the installer...?".
IMHO... No Way! If the installer does something "stupid", it is YOUR fault. You are in a better (technical) position to make the decision.

Seems like a good time for some "technology transfer". Loctite is widely used (successfully) in industry. Take the time to find out (and learn) about it. I've attached a basic "decision tree" on which Loctite product to use for various applications. NONE of the recommendations will apply to your situation... so use engineering judgement. To me, either the low strength (purple) or medium strength (blue) would be a reasonable choice. The nice thing is that even if the threadlocking compound "fails", the leveling nuts will be just fine.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[Tmoose]

Wicking Grade 290 is mighty cool. It's my favorite. If the dispenser hole becomes clogged, be gentle. Enlarging the hole will let it POUR out.

Easy to apply to the top nut, and if the leveling plate is slotted, pretty easy to apply to the under-nut also.

https://ir0.mobify.com/600/https://www.transpo.com/media/k2/galleries/21/Pole-Safe_MG_0047.JPG

It might be easier and "fool proof" to use nuts with nylon locking pellets, but the anchor bolts will need to be nicely deburred to avoid tearing up the pellets.

 

[drawoh]

Tmoose,

How removable is Loctite 290? I was under the impression that was permanent.

--
JHG

 

[SwinnyGG]

The wicking grades are typically approximately equivalent to blue (medium) strength non-wicking formulas.

 

[Tmoose]

http://www.loctite.sg/sea/content_data/93808_290EN.pdf

For Disassembly
1. Remove with standard hand tools.
2. In rare instances where hand tools do not work because of excessive engagement length, apply localized heat to nut or bolt to approximately 250 °C. Disassemble while hot.

270 Works QUITE well on assembled carb adjustment screws that run thru brackets ( limited engagement) that by design may have had a tensioning spring or less. Like the fast idle screw here -

http://carbkitsource.com/carbs/tech/Ford/4100/exploded diagram 4100.jpg

==============
For REAL fasteners in bolted structural joints I concentrate on enlisting proper (sufficient) tightening/clamping and joint preparation and smooth hard washers and ≥ 7 diameters of grip length etc to take loosening out of the equation.
I suppose Adding a little Loctite might help with total fastener loss during the zombie apocalypse, but I would never ask it to prevent structural fastener loosening