ok, I contacted AE. I have never gotten anything but the best support from them. So I decided to post the body of my email and their timely response on this forum.

my email to AE support (sent 1 hour ago)
" I decided to convert my kids sc10 to hex so she could use my SC10 4x4 hex wheels. I picked up a brand new hex conversion on ebay a few weeks ago and finally installed it on friday. After 3 laps at the local track, she was rounding a corner and her wheel fell off. I figured the nut fell off, but that is not what happened. The axle snapped in half. She hadn't even crashed yet. As you can see front the pics, the axle, bearings, hub and caster are all brand new. I have my b4 converted to hex and have crashed it very hard many time and never had an issue. I was running the AE alum front hexes and the same role pins the SC10 RS uses. I am 100% sure the hubs were built correctly. I know things break in racing, but I have been doing this a long time (since 87') and I can always tell when I deserve a break. This broke way too easy."

replay from AE:
"I can send you out the axles. I will also send you out a self addressed envelope to get the bad axles from you."