Bowflex 552 adjustable dumbbells: disc 2

I bought some knock-off (not genuine) Bowflex 552 adjustable dumbbells on Craigslist.  Later discovered that one of the rotating discs was cracked, so that at certain weight setting, one of the weight plates that should have lifted out was getting left in the holder.

The plate that was cracked was the one on the outside, furthest from the handle.  Strangely, when you dismantle the dumbbells, you'll find that this is plate number 2 in Bowflex's numbering scheme.  (Disc 1, presumably, is integrated into the weight-adjustment dial.) 

I found a bunch of other replacement discs online, but I didn't like any of them too much.  One that I printed out didn't work because bumps in the interlock region didn't quite fit the existing discs.   Another version was too loose.   Other ones incorporated the material saving ribs in the original Bowflex discs – which doesn't make much sense for 3D printing.  So I gave up and rolled my own version.  

So far, I only made a model for disc 2, as this is the only one that was broken on my dumbbells. 

UPDATE:  I bought a genuine Bowflex-branded dumbell and discovered that there are a number of small differences between the clone and the original.  Most obviously, the steel shaft that runs through the center of the discs is a slightly different diameter:  Bowflex is 15.9 mm, unbranded clone is 15.7 mm.

If you read the comments, you'll see that someone said they had to scale up their print to get it to fit their dumbbells.  I think the shaft size discrepancy explains why.  I have now included a second file that should work better for genuine Bowflex dumbbells.

Various notes:

• To dismantle dumbbells, pop off the plastic end-caps.  Then use two ¾" (19 mm) socket wrenches to unscrew nuts at each end.  Watch out for springs and ball-bearings that might pop off!  I've found it convenient to tape these parts together.  
• The prominences on the outside of the discs (that support weights) are pretty straightforward:  just divide a circle up into 15 equal parts (24° each).  Bump is either present or not for each sector.
• There are also prominences in the interlocks between each disc that ensure that discs are aligned with each other.  It took me quite a while to figure out what was the pattern for the interlocks, but I'm pretty confident that it's based on the centers of the slots that subtend 30° and 60° arcs for the two smaller and one large prominences.  See screenshot of FreeCAD sketch for details. 
• I printed in eSun PLA+ with 4mm perimeters, and 50% infill.  Seems to be holding up okay.  However, I don't really know why I didn't just print at 100% to maximize strength.