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!
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
RE: how to lock threads in place
Please remember: we're not all guys!
RE: how to lock threads in place
Link
www.SlideRuleEra.net
www.VacuumTubeEra.net
RE: how to lock threads in place
RE: how to lock threads in place
Otherwise just mar the threads.
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RE: how to lock threads in place
Please remember: we're not all guys!
RE: how to lock threads in place
http://henkeladhesivesna.com/blog/the-difference-b...
RE: how to lock threads in place
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
http://www.mcmaster.com/#split-nuts
RE: how to lock threads in place
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
RE: how to lock threads in place
RE: how to lock threads in place
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
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
RE: how to lock threads in place
RE: how to lock threads in place
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
RE: how to lock threads in place
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RE: how to lock threads in place
Also known as "seizing" - used on airplanes!
RE: how to lock threads in place
www.PeirceEngineering.com
RE: how to lock threads in place
RE: how to lock threads in place
RE: how to lock threads in place
RE: how to lock threads in place
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
Dik
RE: how to lock threads in place
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
Look up a CAN/CGSB 7.2-1994.
RE: how to lock threads in place
RE: how to lock threads in place
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
RE: how to lock threads in place