I'm attempting to change the rollers on my kids Dinli Helix 90 and I do not have, and can not find a tool to use on the spider washer...soooo I can not get the nut off as the entire assembly keeps spinning. Where can I find this tool? I have attempted to use a vise grip, a "rubber slip wrench", a pipe wrench, a plumbing nut removal tool (which might have worked if it were smaller).

 

try a impact thats how i got mine off