Once a friend asked about how to anchor an end fed antenna ( such as an EFHW ) at the rig end. A lightweight QRP rig attached to a 67' long wire slung over a high tree limb won't stay put without help. I solved the problem with a "split bolt connector" and some nylon twine.
I found split bolt connectors in the electrical department of my local big box hardware store. The nut, with it's captured cross-piece, screws onto the slotted bolt.
I cut off a couple of feet of nylon twine and looped each end. One loop goes into the split bolt.
Looping the twine around a convenient object (in this case a porch railing) and securing it gives a solid anchor for an end fed wire.