Threaded tube inserts, l.h and r.h threads

While searching McMaster Carr.com today for some work related items, I came across "tube end weld nuts". They're made of 4130 alloy steel and come in a wide range of sizes and thread diameters. They are available in both right hand and left hand threads up to about 1"x 14.
I've already thought of several things I can use them for.
Just type in "tube end weld nuts" in their search box. Hope this is useful to someone other than me.

 

Ya know sometimes while im looking for **** at work i run into really cool **** in the catalog but i missed these completely.. Thanks for the heads up.. If McMaster doesnt have it then
Dave

 

This looks great, thanks for sharing.