[RustyPile]

I did away with the upper joint in the intermediate shaft where it connects to the upper column.. I replaced it with a Borgensen U-joint and needed to lengthen the shaft about 3/4".. Sorry, I didn't take any pictures of the process..

Here's what I did.. No need to heat or otherwise melt the plastic.. First, those aren't pins that go through the overlapping shafts. They're just an "entrance point" to inject the plastic.. The inner shaft doesn't have holes through it. It has 4 square depressions beneath the 4 holes in the outer shaft. These depressions capture the plastic and maintain a relatively snug slip fit between the 2 shafts.. Melt, or otherwise, remove the plastic in those depressions and the 2 shafts will rattle against each other. Drill through the 4 holes just enough to penetrate the outer shaft.. Clamp the outer shaft in a vice and push the inner shaft deeper into the outer shaft until you have the length you want..