Trying like hell to find the tutorial I used on RWGForum, But essentially it's this:
tools:
1 inch thick block of wood
drill bit (a couple of mm bigger than the hex tube
3.3mm cobalt bit
Hardened steel screw or nail (turned down to the exact exterior diameter of the old tube)
pipe wrench
drill press
marine epoxy
I followed a tutorial on RWGJr to make a jig with a block of wood.
Measure the exterior diameter of the tube from the inside of the case
Find a nail with that exterior diameter, trim the tip off so the remainder is about 20mm long
chuck the head of the nail in your hand drill or press so about half of it is exposed
turn the nail down to the inside diameter of the tube by holding a file to it while it is spinning
Drill a hole in the block of wood bigger than the hex tube
(You've just made your jig)
Remove the crystal
line up the exterior of the hex on the hole in the wood
Place the nail in the tube on the inside of the case
open your pipe wrench wide
one jaw goes on the outside of the wood the other goes on the head of the nail
squeeze
tube pops out eeasily drill out empty tube hole to 3.3mm
lightly and evenly coat the outside of the DSN tube with marine epoxy
press in place with your thumb
drink a beer or bourbon or, if its summer in Europe: have a Campari