Has anyone seen a fastener like this before? I was trying to remove the casters from a dolly cart to give it some R&R and encountered this fastener which seems to have no normal means of removal. The head look like a carriage bolt head, and the shaft is threaded, but the nut looks more like nut-sert. How were these tightened to begin with? Why would they use something like this? Thanks for any info.


