This burr only uses three different types of parts. 6 long parts, and 18 short parts. Two of the short parts have a notch cut out of them to allow the puzzle to actually be assembled.
The pieces are all cut from a square cross section. If you take the width of the piece to be one unit, then the short pieces are three units long, with a two unit wide notch, and the long pieces are six units long, with a five unit wide notch. The notches cut to a depth of half a unit.
I used 18 mm as my "unit" sizes, so the long pieces are 18x18x108 mm in size. If you build one, be sure to make the notches just slightly wider and deeper than whole unit sizes, so the puzzle won't jam up when you assemble and disassemble it.
In its assembled form, the puzzle consists of six assemblies like the one shown at left.
After the first assembly is built, the other assemblies are built, one at a time, in place.
The notched pieces are necessary to build the assemblies in place. The notched piece is placed last. To place it, one of the long pieces is pulled back, and the notched piece is dropped in place. Its the right-most piece in the photo at left.
The last assembly goes in just like the second last assembly.
I made a video showing how this puzzle goes together.