Need some help solving a small design problem

[tehdizzy]

So it seems pretty basic, but I'd like to get some input/ideas from some other people.

I have a PVC pole (3.25 OD) in which I'm trying to attach a shelf to the outside. I need something to pass through the pole on the inside, so bolts/screws etc will not work. I've used various types of glue, and they work well, but I'd like to have some sort of physical stop/hold.

I was wondering if anyone had any suggestions on a way to keep it held up on the outside? I'm looking into using some type of rubber o-ring or rubber band with high enough strength to hold the shelf. I have been unsuccessful finding something on the internet that will work though, so if anyone could direct me it would be much appreciated.


PoleShelf.jpg
The shelf is really lightweight, so I think some sort of rubber stop may work well. I just can't seem to find one anywhere.

Thanks for the help!

[RWOLFEJR]

Hose clamp. (ugly but easy)
Lock collar. (pretty but little more $$)
Shallow Groove machined in tube for collar etc. (Better mechanical certainty but machining costs)
Second tube slid over the tube. (simple... pretty? but added material cost for 4" ? pipe.)

You might want to look at metal shelving found in a lot of restaurants. Round posts and the shelve accept thin sleeves. I never inspected them to the umpteenth but I expect they have a very slight taper because when swatted into place the inserted sleeve acts like a collet and grips the pole.