I recently moved and the local wall has t-nuts that can't be swapped out. It's some sort of old fiberglass panel type of thing. Anyway, some of the nuts are cross-threaded to the point of uselessness. Does anyone see any issue with running a tap into these holes to straighten out the threads? I'm sure they will be slightly weaker and prone to becoming cross-threaded again, but I think it should be better than not using the holes.
tapping cross threaded nuts
(9 posts) (6 voices)-
Posted 1 year ago #
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nope, it'll probably be fine to do that
Posted 1 year ago # -
If that doesn't work, and you can access the back of the walls, you can probably take out the bad t-nut (or clean it out so it's just a metal sleeve) and screw a piece of plywood with a new t-nut in it behind the old one...
Posted 1 year ago # -
Some of the really old EP fiberglass panel systems had the t-nuts embedded in the fiberglass, to where removing the old one would damage the visual finish of the exterior side of the wall panels.
If that's what you're dealing with, you can use a slightly larger diameter drill bit and drill out the existing t-nut (basically removing the threads from it) and then epoxy a new t-nut (backwards) directly behind the old one. When doing this, it's best to thread a hold bolt into this new t-nut to keep it properly aligned while the epoxy sets up.
I've done this a few times with good results.
Posted 1 year ago # -
The t-nuts are embedded. I had considered drilling out the nuts and mounting new ones in behind, but the panels are about 2 inches thick over most of their surface. This would necessitate either long bolts for these spots or drilling a countersink on the back of the panel, both of which I would like to avoid.
Posted 1 year ago # -
I am a mechanic by trade and I would advise you to get a "re-threader" rather than at tap to save damaged T-nuts. A tap as sharp cutting edges which will remove any metal that does not conform to the thread pitch, leaving you with much thinner and therefor weaker threads in your T-nut. A rethreader will actually push most of the damaged metal back into position, reforming the threads and leaving you with a much stronger nut.
Posted 1 year ago # -
Thanks Kent, That's a good idea. I don't own a re-threader set but it would definitely be worthwhile for the gym to have one. I'm going dig up a 3/8" rethreader, try it, and see how the nuts hold up before I start drilling holes out and mounting new nuts.
Posted 1 year ago # -
Kent, good beta, which re-threader do you use? Would a "thread restorer" do the same thing?
Posted 1 year ago # -
A thread restorer is the same thing, I think. The basic difference is when you look at a tap it has 3 or 4 sharp cutting edges. A re-threader is blunted and does not have the deep channels along the cutting edge.
Posted 1 year ago #
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