To answer the OP's question, there are a few ways to do this.
You can bypass this problem entirely with rivets or rivet nuts, as previously mentioned. If you are installing bolts the OTHER way (as in Bolt Head -> Tubing -> Thing You Are Screwing The Bolt Into), you can drill a tool clearance hole through one side (3/8 works well for a #10 screw).
The other method that Greg touched on is to insert some kind of material inside the tube. Wood is a great choice as it is rigid and light - I am honestly surprised more teams don't use wood inserts to increase tube strength for very little weight. If you are looking for something you can tap, a smaller plastic insert (delrin) can work pretty well depending on how much load those threads will see.
Finally, depending on how much tube access you have, if its easy, just slide your favorite kind of hollow tubing in the hole and run the bolt through its center.
If you can't avoid it, washers will help slow down the crushing process which helps I guess. Don't use .04 wall tube without support in this manner!
Quote:
Originally Posted by Oblarg
We've been experimenting with these in the preseason, and our impressions have been generally good. I've heard some complaints about them coming loose and spinning in their holes, though - we might try dabbing the outside of them with some red loctite before installation to prevent this.
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As long as they are installed properly, this should not be an issue, especially if you get the rivet nuts with the knurling on the outside. If this happens, then you haven't been installing rivet nuts fully and need to redo this.
A properly installed rivet nut can take a lot of load. We lifted our robot via four eye bolts screwed into four rivet nuts in the chassis. This is something I was very nervous about until we actually did it and tested it, but rivet nuts can do the job!