Fastener question

I need some help with a project: Our club has a portable layout that we haul from place to place. The legs consist of PVC pipe with plastic caps equipped with leg levelers. The levelers currently use a threaded brass furniture insert with a carriage bolt threaded inside and the legs are leveled by rotating the bolt. The problem is that this is a kind of cobbled approach. What we REALLY need is an "insert" (for lack of a better term) that is made of steel (brass is too soft) that is about 1/2" in ouside diameter with a machine thread, maybe 1/2 x 13, and an inside 1/4 x 20 thread. It needs to be at least 3/4" long. 1" would even be better. Does anyone know where we could find something like this, or failing that, where we could get 50 or so manufactured? Jeff

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Would this do:
http://www.happcontrols.com/amusement/billiards/49099702.htm
Or this:
http://www.etundra.com/Table_Leveler_w__Metal_Base___1_4__x_3_4__Stud-P1338.html
Google is your friend:
http://www.google.com/search?q=table+leg+levelers
And:
http://www.google.com/search?q=threaded+insert
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Perhaps the term "insert" is getting in the way. Everything I have found so far is a self-tapping product. What I really need is something that I can fasten into my leg caps with nuts, so it needs to be at least 3/4" long, preferably 1" Jeff

-- http://www.deepsoft.com/ModelRailroadSystem /
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How about a wood plug with the inside diameter of the cap. screw it in from the sides so it won't move. drill it and the cap then remove the plug and put a T nut in and put the plug back and then the cap on the leg.

The problem we have had with T-nuts is that they cannot withstand the lateral forces of moving the modules around, or even the flexing that occurs when the modules are leaned on during the normal course of operation. Those with tabs pull out, even if secured with adhesive, and those with screw mounting require screws so small that they pull out of the wood. Believe me, we have tried virtually everything with T-nuts. Jeff

On 8/22/2009 11:14 AM Jeff Stanton spake thus:
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I'd look into ordinary T-nuts, like these: (Amazon.com product link shortened)
(you can get ones with longer, skinnier prongs than this)
They'd go on the bottoms of the caps, on the outside, so the weight of the layout would hold them tight. Drill a center hole for the screw and four small holes for the prongs, maybe use a dab of epoxy to keep them from falling out.
Much cheaper and easier to obtain than Robert's pool-table-leg levelers.

David Nebenzahl wrote:
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We tried the T nut rout for our 2x2 legs on our club layout. The nuts kept falling out, the bolts would vibrate out and in general it was unsatisfactory. We changed to EZ-Lok inserts and hammered the threds befor inserting into the legs. No more problems.

On 8/22/2009 3:14 PM Chuck Kimbrough spake thus:
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There's another kind of T-nut that hardware stores have in the "nifty little miscellaneous parts" section, that has 3 holes instead of prongs. One could fasten these to the PVC caps with sheet metal screws, which ought to hold them in pretty well.

David Nebenzahl wrote:
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Or you could just forego the caps, epoxy dowel into the end of the legs, and use plain ole tee nuts. A jam nut threaded onto the elevator bolt will lock the bolt in position, and allow for easy adjustment.
fl@liner

Thanks to all for your help. We have tried all the mentioned variations of T-nuts, but none can stand up to lateral forces generated when the position of modules is shifted. What we really need is some sort of threaded insert that can be securely bolted into the cap. In addition, we have found that epoxy or similar products just don't hold well in PVC pipe. Jeff

On Sun, 23 Aug 2009 08:36:05 -0400, Jeff Stanton wrote:
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Jeff, how about a piece of 1/4" pipe threaded on both ends so it can be bolted into the leg? The problem to me would seem to lie in the thinness of the pipe cap. Perhaps you could find smaller PVC pieces that could be used to reduce the inside diameter of the leg to the same as the pipe outside diameter. If so, you might not need the pipe. Then install a long machine screw and secure it. I would even consider epoxying it in.

The club I belong to uses eye-bolts threaded into nuts in the caps. Looks a bit flakey, but you can then use a rod to turn the eye-bolt when leveling the module. We then use a 3/4" piece of ply 6" square between the ground and the eye-bolt when we're on dirt instead of concrete. Have had the occassional problem of the nut popping loose, but we keep spares on hand during shows.. The modules themselves are light enough that we just get a few members together and lift them when we need to move them. Can't recall what we use to glue the nuts onto the caps with though - probably epoxy, but maybe some of the newer 'gorilla' glues would work as well...
Matt
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Actually, I'm getting a little closer to a solution. It appears that the simplest solution is something called a reducing bushing. They make them with a male thread of 1/2" and a female thread or 1/4". Unfortunately, the female thread is a pipe thread, and I need a 1/4 x 20 machine thread. The male thread can be almost anything. I may have to find someone to custom make them for us. I appreciate all of the suggestions offered here, but many of them would require us to go back almost to square one. Our legs and leg end caps have been purchased or constructed, and all we need is a reliable adapter to mount the leg levelers. Jeff

On 8/23/2009 5:16 PM Jeff Stanton spake thus:
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I was going to write, before my Usenet access was so rudely cut off, that what you need is one of these--
http://www.plumbingsupply.com/images/pvc-fitting-439-threaded-bushing-mipsxfips.jpg
--except not plastic and with machine threads, as you pointed out.
Regarding threads, I wonder if you couldn't just buy plumbing bushings and re-tap the threads with a regular tap to remove the taper? I think the FIP threads are the same as regular machine threads, except tapered.

wrote:
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http://www.plumbingsupply.com/images/pvc-fitting-439-threaded-bushing-mipsxfips.jpg
You also get threaded plumbing adapter and use *steel* caps instead of plastic ones. You can drill and tap the *steel* cap. Or if more ambitious, get a solid steel plumbing plug, and drill and tap that. You'll probably want a (heavy duty) drill press for this.
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How about something like this? http://www.empiredistribution.biz/nut.html
They're called "insert nuts" and I've found them at my local hardware store. The style I got drive in with a hex wrench, then the machine thread bolt inserts into the center.
Puckdropper

On Sat, 22 Aug 2009 14:14:33 -0400, "Jeff Stanton"
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Trying a different tack: how about three-legged trestles and put the levellers at the top between the legs and the layout boards?
Tim

On 8/22/2009 11:14 AM Jeff Stanton spake thus:
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Just ran across this page and thought this guy's shop-made leg levelers looked interesting (near bottom of page):
http://www.iedu.com/DeSoto/Projects/RadialArmSaw
Of course, you couldn't use these with your pipe legs, but they would work nicely with wood legs.