@Pun1sh3R @Sleeper80 I thought I’d respond over in this thread to keep the fixed-axle February thread on topic.
It’s possible that there was some unseen defect in the walnut dowel used for these. I inspect the dowel portions I use, but it’s always possible there was a flaw that wasn’t visible.
I’ve had a c-grade yoyo with a 1/4” walnut axle that didn’t make the cut sitting around and decided to use it for a stress test. I clamped it pretty hard on the edges and it took a significant amount of pressure to break it in half. Like, I had to aggressively try with my hands to finally snap it.
It makes me think that the ones that snapped definitely could have had a bad dowel section. I mean hard whacks and doing outdoor chores with it in the pocket probably don’t help either 
, but still.
Another good reason I’m trying 5/16” and 8mm axles in some alternate woods. I really like how walnut plays, and I like the spin time of a 1/4” axle, but it’s definitely a bummer to get a yoyo and have it break on you. Either way, I’ll get these fixed and back in commission soon.