Designed in 2012 by really prolific puzzle designer Stephane Chomine (who has a whopping 497 designs to-date), the Coaxial was another non-starter for me.
Made by Pelikan to the usual high standards out of Maple and Wenge, this interlocking solid does not sport the more usual box frame style. Instead it consists of 6 pieces, three of which are regular burr units while the "frame" is made up of another three odd-shaped pieces; pairs of square rings each joined by a spar and with protrusions.
While it has a 22.214.171.124.2 solution (ie 17 steps to remove the first piece), not a lot compared to some other interlocking burrs, some with well over a 100 moves, the Coaxial is, in my view very difficult. I got stuck around step 10 and could proceed no further. No amount of trying, random or otherwise yielded any luck. Fortunately for me the good folks at Pelikan provided a printed solution to help and Burr Tools took care of the re-assembly.
Coaxial is currently available via PuzzleMaster of Canada for CA$49.99.