https://www.amazon.com/Z-Threaded-Insert-Internal-Threads/dp/B0026GZU0Q/ref=mp_s_a_1_4?dchild=1&keywords=3%2F8+beer+tap+handle+nut&qid=1617817359&sr=8-4 Something like this. Pre drill the tap handle and then sink the nut with a screw driver. Check YouTube for some videos. It can be finicky.