Another way is to bore a hole in a piece of 3/4" ply to fit the small
pipe and then cut out a disk with the hole in the center to fit inside
the larger one. Clear? Hummmmm...well you are really making a bushing
right? Cheap, easy and you don't have to make another trip to the
hardware store.
DD
PS A bit of duct tape is also needed...

"It's easy when you know how..."
Johnny Shines