# T-nuts vs threaded inserts



## Erik07 (Feb 16, 2021)

Hey all, I have a project coming up that I was hoping to get some input on. I'll be making a table base for a glass table top and intend to put some leveling feet with 5/16-18 thread underneath. Typically I discard the t nuts they come with and replace with threaded inserts since I find it easier to make the holes.

I've made relatively small tables until now without a problem, but my concern is that a real heavy table could work the threaded insert loose. I imagine this happening either from the compression into the hole and/or the lateral forces. I put jb weld on the threads as well.

Any opinions on whether I'm overthinking it or whether I should switch to t nuts?

Thanks!


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## wapakfred (Jul 29, 2011)

I've used threaded inserts for that and never had them work loose. I have, however, had t nuts come out….the little "fingers" that get hammered in aren't as reliable as the threaded approach, especially on the end grain of legs.


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## JAAune (Jan 22, 2012)

I've had a couple threaded inserts come loose on me so I prefer T-nuts or cross dowels. From a mechanical standpoint, t-nuts are much stronger at resisting pulling force (if going through the material).

I doubt you'll have a problem if the inserts are glued (t-nuts should be glued too) in but I've always found t-nut installation easier and less finicky.


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## rwe2156 (May 7, 2014)

It would not be a good application for T nuts.

Even though the force is right direction. Eventually it will become loose.

That said it could be secured with a small screw that overlaps the rim.


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## LesB (Dec 21, 2008)

I support the threaded inserts. The will be a little harder to install parallel with the legs.

You could epoxy the T nuts in to help resist their pulling out.


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## RClark (Jun 1, 2012)

I have a 4' X 4' outfeed table for my tablesaw. The outfeed also serves as my primary workbench for all manner of projects, not just woodworking. The table weighs about 400 pounds.

The leveling feet underneath are just carriage bolts threaded into T-nuts in the bottom of the 4X4 legs. If I recall correctly, they're 3/8" bolts. I've had no issues over the past 5 years with this setup.


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## drsurfrat (Aug 17, 2020)

the compression seems like either would be fine, but for lateral movement, the flange on the t nut might be a bit better. There is also the option for a better tee nut with screws instead of pointy bits.


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## JackDuren (Oct 10, 2015)

> I ve used threaded inserts for that and never had them work loose. I have, however, had t nuts come out….the little "fingers" that get hammered in aren t as reliable as the threaded approach, especially on the end grain of legs.
> 
> - Fred Hargis


Same here. No problems if installed correctly…


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## CWWoodworking (Nov 28, 2017)

Use polyurethane glue on threaded inserts. They won't come loose.

I little goes a long way.


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## Tony1212 (Aug 26, 2013)

I've adopted the John Heinz/Mattias Wandel method of installing T-nuts where possible. I use a #4×1/2" pan head screw right in the voided area where the hammer point thing was cut and pushed up.










The only con here is that it doesn't work if you need it to flush with the top of the T nut.


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## bigblockyeti (Sep 9, 2013)

I use T-nuts when I can, and good T-nuts are a must (Lowe's & HD do not sell good T-nuts). In compression, they have greater bearing area and are typically steel instead of brass or cast pot metal. I counterbore the surface they will be installed into to the depth of the flange thickness, I also counterbore for the body of the nut and bore only for clearance the thread of the screw going through. Having the steel screw extend 2-3" into the work beyond the T-nut in a bored to fit hole transfers lateral forces into the wood vs. just into the T-nut trying to pry it out of its bore.


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