I tried the anchor method but couldn't get the anchor to hold tight, probably a size issue. I had some 5/16 oak dowel lying around. Running a 5/16 inch drill inside the handles removed the inside lip left by the pipe cutter when the handles were made, at which point the dowel fit in fairly snuggly but not super tight. I cut four 2 inch lengths of dowel, drilled a 3/32 hole 1/4 inch from the end and used some old epoxy to glue these into the handles to remove any chance of them moving. I also added some heat shrink tubing I thought would make it hard for the end caps to move. As others note, this makes the handles a little longer, but these were my original short pair anyway.