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how to lock threads in place
4

how to lock threads in place

how to lock threads in place

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

RE: how to lock threads in place

Could you have them damage the threads?

RE: how to lock threads in place

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

Please remember: we're not all guys!

RE: how to lock threads in place

"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

www.SlideRuleEra.net idea
www.VacuumTubeEra.net r2d2

RE: how to lock threads in place

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).

RE: how to lock threads in place

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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RE: how to lock threads in place

(OP)
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!

RE: how to lock threads in place

I would use Loctite 290 (note the spelling)

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

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

RE: how to lock threads in place

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.

RE: how to lock threads in place

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.

RE: how to lock threads in place

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.

RE: how to lock threads in place

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...

RE: how to lock threads in place

(OP)
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!

RE: how to lock threads in place

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

RE: how to lock threads in place

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.

RE: how to lock threads in place

"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

RE: how to lock threads in place

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

RE: how to lock threads in place

2
Why not just take some tie wire and wrap around the handles and 16d nail (or the backed off lag bolt heads)?
Also known as "seizing" - used on airplanes!

RE: how to lock threads in place

Sawbux, you beat me to it with that answer. Wiring to one or two nails beats permanently buggering up the threads.

www.PeirceEngineering.com

RE: how to lock threads in place

Quote (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.
In my experience, they only loosen when the footing settles or the wood shrinks. I don't think vibration will do it.

RE: how to lock threads in place

put in a pipe between the handle and the end of the col....pipe with dia to fit over threaded portion...cut the pipe in half length-wise....secure in place with hose clamps or similar....

RE: how to lock threads in place

attach metal strap to side of beam with a hole in it to capture one handle.....

RE: how to lock threads in place

Typically, Loctite is applied on the threads PRIOR to assembly. Asking it to wick down far enough to do something useful in this case might be a bit of a stretch. Nevertheless, Loctite makes dozens of varieties their basic product, and they might have a particular formulation for your situation.

If the tenant above runs a few kilowatts of speaker power, I could imaging sufficient vibration to start shaking the jack loose. One option that is used in aerospace systems for something more secure than Loctite is "staking." This would involve drilling a hole through the flange into the thread and jamming a pin into the hole. You can make that even more permanent by splitting the pin with a wedge after installation. This is something you could possibly undo, if you really wanted to.

Barring that, you could just drill and tap for a set screw. Loctite the set screw and since the load on the set screw is low, it shouldn't move one way or another unless someone forcibly moves it.

TTFN (ta ta for now)
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RE: how to lock threads in place

Try a perforated steel pipe hanger strap looped around the handle and screwed to the wood beam over... easy to adjust if necessary.

Dik

RE: how to lock threads in place

SLTA:
Since their inception as a construction product these adjustable columns have been installed as your photo shows. They are intended to be adjustable for a number of reasons and conditions. The adjusting handle can usually be pulled out of its hole in the threaded rod/bolt to prevent some numskull from playing with it, in the wrong way. Then some extra smart AHJ decided you could void the adjustability feature, and eliminate the numskull issue by just adding/codifying the stupid idea of turning the column upside down and encasing the threaded rod in concrete. Now, they will need some new laws and code req’rmts. which prohibit anyone with a hack saw, any power saw, wire cutters, jack hammer or cutting torch from entering the city limits, so they can’t mess with those columns.

The fact that you have seen some of these columns loose, just means that some people were too dumb or lazy to take advantage of the adjustability feature, likely not because someone messed with it intentionally. Also, I’ve seen the columns rusted out at the bottom, and as likely as not the footing has settled, neither condition is the fault of the exposed threaded rod. When we have to start designing structures, and using construction products which are stupid proof, we are in big trouble, because there are just too many of those people out there.

RE: how to lock threads in place

I agree with Dhengr... And posts just like this ar installed in just about every single residential home in Canada. Even worse, by US AHJ standards, they are multi-length adjustable and made from one tube loosely fitted into another with a shear lug.

Look up a CAN/CGSB 7.2-1994.

RE: how to lock threads in place

As others suggested, some stainless steel lock wire of the appropriate gage securing the handle to the beam would work nicely. Just make sure you install the lock wire in the correct position.

RE: how to lock threads in place

If you do choose to damage the threads, keep in mind that this will prevent the adjustable portion from rotating only in the direction to make the column shorter. One will still be able to rotate it in a direction to lengthen the column, something that will be useful for any future adjustments for settlement.

There are many, many residential houses in my area with adjustable columns (tele-posts) with exposed threads. Nothing major will happen as long as the top and bottom are securely fixed. I worry more about the home renovators who remove interior columns completely, without any form of beam reinforcement. I have come across this twice so far and lucky for them no major damage occurred, after several years, only a couple of inches of extra deflection. Could have been much worse.

RE: how to lock threads in place

You could mouse it like a shackle.

RE: how to lock threads in place

I'm with others who question if this needs to be secured at all. If this was a built-up 2x6 post would we be discussing how to keep people from cutting it to pieces or drilling a large hole in it? You've provided them with a sound structure, if someone comes along and decides to compromise the structure there really isn't much you can do about it. I've seen people go through great lengths to make some terrible decisions - sometimes you can't outsmart stupid.

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