how to lock threads in place 4

[SLTA]

I spec'd out a retrofit adjustable locking column from Akron Products (

http://www.akronproducts.com/adjustable-columns.html)

for a residential renovation job recently. I've found these columns to be great replacements for old rusted-out jack posts. The contractor, bless his heart, didn't give his guys my details on how to install the blasted things, so they put them in upside down and hence, the adjustable portion is at the top of the column instead of locked into place in concrete at the base.

The columns were installed appropriately otherwise, so now I'm trying to figure out what the contractor can put on the threads of the adjustable portion to lock the column height into place. I'd rather not have them tear out the columns for a variety of reasons. So, does anyone have a suggestion? I was thinking something like the J-B SteelStik Epoxy Putty or the J-B Weld, and having them smear it all around where the threads meet the column. Anyone have a preferred product, or experience with the J-B products?

Thanks!

Please remember: we're not all guys!

 

[SteelPE]

Could you have them damage the threads?

 

[SLTA]

That was my other thought - I guess I was looking for something more consistent (and yes, elegant).

Please remember: we're not all guys!

 

[SlideRuleEra]

"Locktite" is a product made for this purpose. It is widely used in industry on machine fasteners. Comes in a range of strengths, from temporary to essentially permanent. Suggest calling a rep to get a specific recommendation for this use. See this link:

Link

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[SteelPE]

Locktite was my other option? Not sure how it performs with paint though. The green is a b***h to get moving (you need to heat it up).

 

[JAE]

Could you weld small steel tab plates from the upper plate down to the small cross rod - this would prevent rotation of the screw but yet still allow the plates to be removed in the future if the column needs to be adjusted.

Otherwise just mar the threads.

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[SLTA]

Welding is out - this poor house would go up in smoke. I'll look into the Locktight stuff. Cheers, folks!

Please remember: we're not all guys!

 

[SteelPE]

This link from the mfr says only metal to metal applications, so locktite might be out.

http://henkeladhesivesna.com/blog/the-difference-between-red-blue-green-and-purple-threadlockers/

 

[MikeHalloran]

I would use Loctite 290 (note the spelling)

http://www.loctiteproducts.com/tds/T_LKR_GREEN_tds.pdf

because it won't bond to the paint, but it will wick into the joint, find the areas where the contact is metal to metal, and bond that.

If there is a similar product recommended for larger diameter threads, I wouldn't use it, so the homeowner might have a small chance of adjusting the jacks later. If you someday get a call about loosening the stuff, suggest a gigantic soldering iron or an induction heater; at 400F or so, the stuff turns to liquid and allows motion. Below that temperature, I have not seen it fail from mechanical stress.

* Absent instructions, I'd have installed the posts threads up, on the assumption that the cross-bars would be real ankle-biters.




Mike Halloran
Pembroke Pines, FL, USA

 

[theonlynamenottaken]

How about a jam nut?

http://www.mcmaster.com/#split-nuts

 

[KootK]

I'd think that one could achieve a reasonable degree of tamper-proofing by hacksawing off the handles.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Ron]

Gall the threads with hammer and chisel. Locktite and others can be ineffective on some paints. Another option is to drill a small hole through the threaded rod, either all or part way and put a roll pin in the hole.

 

[XR250]

why is it any more likely to loosen when installed threaded end up? I would leave it alone as it may need adjustement later. These things are incredibly hard to turn when there is weight on them. Usually, you have to put a temp. hydraulic jack next to them to get any meaningful lift.

 

[EngineeringEric]

pinch a handle between 2x hangers extending down the beam... pinching one handle to keep it from spinning may work?

i second mechanical deformation if possible or maybe try clamping a mechanical splice or something over the threads...

 

[SLTA]

XR250, the proper installation of these columns has the handle encased in concrete above the concrete footing, so that only solid steel pipe is above ground. I've been in so many houses where the jack posts have loosened to where you could wiggle them by hand.

Ok folks - the damaged threads win out. Thanks to everyone for the help!

Please remember: we're not all guys!

 

[richline]

The cap plate doesn't appear to be seated properly because of the slight rotation. Can the handle be removed?

 

[BUGGAR]

I suggest leaving the threads alone to allow for adjusting for future cross grain shrinkage, although no one will likely ever go down there and adjust the thing. I would give the job to JAE.

 

[Tmoose]

"I've been in so many houses where the jack posts have loosened to where you could wiggle them by hand. "

I'm not sure I'd attribute that to threads spontaneously unscrewing or being unscrewed. Or similarly tightening of the adjacent posts.
Wouldn't a little differential shrinking/settling and multiple posts under a single beam leave some posts doing all the work, and one or a few just along for the ride?

Like others said, having the threads available in the future take up the load on the slackers or true up the floor might come in handy.

A split collar fitted with tamper resistant proof torx head screws clamped on the thread would be a moderately effective barrier to tampering or loosening during stomp parties.

http://www.ruland.com/ps_collars_shaft_sp.asp

 

[EngineeringEric]

As nice as future makeup would be, the intended design does not allow this to happen. Maybe this could be an improvement due to this modified condition but is it truly necessary for residential serviceability concerns? I'd say not but this is just one under-cafinated opinion

 

[JAE]

BUGGAR - unfortunately I'm not a welder!

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