Top video thanks. Looks like not crushing the tubes gonna be the tricky part. All my parts got here today and i'm stripping the frame now. I may have to throw it together & ride 1st. Who's bidding against me on my blue bird seat on ebay?!?! I already bought paint...
I've done another 5 or 6 sets since making that video and tapping that bottom threaded area is still my most successful technique for getting them loose. Be careful not to overdo it, since you're actually stretching the tube and increasing the diameter.
You'll start to see a little rusty dust come out of the joint as you tap the area with a hammer. That let's you know it's working and breaking up the rust inside. Just take your time. Sometimes I start adding a few drops of penetrating oil to the joint area as I tap, especially when I see that powdery rust exiting the joint. Just keep rolling it evenly on a hard flat surface, like the top of a vice jaw as you tap.
I've also noticed that it sometimes helps to work the joint back and forth, tightening and loosening to work that oil into it.